diff --git a/fast/stages/02-networking-nva/README.md b/fast/stages/02-networking-nva/README.md
index a72519b50..ca4d3bcae 100644
--- a/fast/stages/02-networking-nva/README.md
+++ b/fast/stages/02-networking-nva/README.md
@@ -387,7 +387,7 @@ DNS configurations are centralised in the `dns-*.tf` files. Spokes delegate DNS
 | [region_trigram](variables.tf#L183) | Short names for GCP regions. | <code>map&#40;string&#41;</code> |  | <code title="&#123;&#10;  europe-west1 &#61; &#34;ew1&#34;&#10;  europe-west3 &#61; &#34;ew3&#34;&#10;&#125;">&#123;&#8230;&#125;</code> |  |
 | [router_configs](variables.tf#L192) | Configurations for CRs and onprem routers. | <code title="map&#40;object&#40;&#123;&#10;  adv &#61; object&#40;&#123;&#10;    custom  &#61; list&#40;string&#41;&#10;    default &#61; bool&#10;  &#125;&#41;&#10;  asn &#61; number&#10;&#125;&#41;&#41;">map&#40;object&#40;&#123;&#8230;&#125;&#41;&#41;</code> |  | <code title="&#123;&#10;  landing-trusted-ew1 &#61; &#123;&#10;    asn &#61; &#34;64512&#34;&#10;    adv &#61; null&#10;  &#125;&#10;  landing-trusted-ew4 &#61; &#123;&#10;    asn &#61; &#34;64512&#34;&#10;    adv &#61; null&#10;  &#125;&#10;&#125;">&#123;&#8230;&#125;</code> |  |
 | [service_accounts](variables.tf#L215) | Automation service accounts in name => email format. | <code title="object&#40;&#123;&#10;  data-platform-dev    &#61; string&#10;  data-platform-prod   &#61; string&#10;  gke-dev              &#61; string&#10;  gke-prod             &#61; string&#10;  project-factory-dev  &#61; string&#10;  project-factory-prod &#61; string&#10;&#125;&#41;">object&#40;&#123;&#8230;&#125;&#41;</code> |  | <code>null</code> | <code>01-resman</code> |
-| [vpn_onprem_configs](variables.tf#L229) | VPN gateway configuration for onprem interconnection. | <code title="map&#40;object&#40;&#123;&#10;  adv &#61; object&#40;&#123;&#10;    default &#61; bool&#10;    custom  &#61; list&#40;string&#41;&#10;  &#125;&#41;&#10;  peer_external_gateway &#61; object&#40;&#123;&#10;    redundancy_type &#61; string&#10;    interfaces &#61; list&#40;object&#40;&#123;&#10;      id         &#61; number&#10;      ip_address &#61; string&#10;    &#125;&#41;&#41;&#10;  &#125;&#41;&#10;  tunnels &#61; list&#40;object&#40;&#123;&#10;    peer_asn                        &#61; number&#10;    peer_external_gateway_interface &#61; number&#10;    secret                          &#61; string&#10;    session_range                   &#61; string&#10;    vpn_gateway_interface           &#61; number&#10;  &#125;&#41;&#41;&#10;&#125;&#41;&#41;">map&#40;object&#40;&#123;&#8230;&#125;&#41;&#41;</code> |  | <code title="&#123;&#10;  landing-trusted-ew1 &#61; &#123;&#10;    adv &#61; &#123;&#10;      default &#61; false&#10;      custom &#61; &#91;&#10;        &#34;cloud_dns&#34;, &#34;googleapis_private&#34;, &#34;googleapis_restricted&#34;, &#34;gcp_all&#34;&#10;      &#93;&#10;    &#125;&#10;    peer_external_gateway &#61; &#123;&#10;      redundancy_type &#61; &#34;SINGLE_IP_INTERNALLY_REDUNDANT&#34;&#10;      interfaces &#61; &#91;&#10;        &#123; id &#61; 0, ip_address &#61; &#34;8.8.8.8&#34; &#125;,&#10;      &#93;&#10;    &#125;&#10;    tunnels &#61; &#91;&#10;      &#123;&#10;        peer_asn                        &#61; 65534&#10;        peer_external_gateway_interface &#61; 0&#10;        secret                          &#61; &#34;foobar&#34;&#10;        session_range                   &#61; &#34;169.254.1.0&#47;30&#34;&#10;        vpn_gateway_interface           &#61; 0&#10;      &#125;,&#10;      &#123;&#10;        peer_asn                        &#61; 65534&#10;        peer_external_gateway_interface &#61; 0&#10;        secret                          &#61; &#34;foobar&#34;&#10;        session_range                   &#61; &#34;169.254.1.4&#47;30&#34;&#10;        vpn_gateway_interface           &#61; 1&#10;      &#125;&#10;    &#93;&#10;  &#125;&#10;  landing-trusted-ew4 &#61; &#123;&#10;    adv &#61; &#123;&#10;      default &#61; false&#10;      custom &#61; &#91;&#10;        &#34;cloud_dns&#34;, &#34;googleapis_private&#34;, &#34;googleapis_restricted&#34;, &#34;gcp_all&#34;&#10;      &#93;&#10;    &#125;&#10;    peer_external_gateway &#61; &#123;&#10;      redundancy_type &#61; &#34;SINGLE_IP_INTERNALLY_REDUNDANT&#34;&#10;      interfaces &#61; &#91;&#10;        &#123; id &#61; 0, ip_address &#61; &#34;8.8.8.8&#34; &#125;,&#10;      &#93;&#10;    &#125;&#10;    tunnels &#61; &#91;&#10;      &#123;&#10;        peer_asn                        &#61; 65534&#10;        peer_external_gateway_interface &#61; 0&#10;        secret                          &#61; &#34;foobar&#34;&#10;        session_range                   &#61; &#34;169.254.1.0&#47;30&#34;&#10;        vpn_gateway_interface           &#61; 0&#10;      &#125;,&#10;      &#123;&#10;        peer_asn                        &#61; 65534&#10;        peer_external_gateway_interface &#61; 0&#10;        secret                          &#61; &#34;foobar&#34;&#10;        session_range                   &#61; &#34;169.254.1.4&#47;30&#34;&#10;        vpn_gateway_interface           &#61; 1&#10;      &#125;&#10;    &#93;&#10;  &#125;&#10;&#125;">&#123;&#8230;&#125;</code> |  |
+| [vpn_onprem_configs](variables.tf#L229) | VPN gateway configuration for onprem interconnection. | <code title="map&#40;object&#40;&#123;&#10;  adv &#61; object&#40;&#123;&#10;    default &#61; bool&#10;    custom  &#61; list&#40;string&#41;&#10;  &#125;&#41;&#10;  peer_external_gateway &#61; object&#40;&#123;&#10;    redundancy_type &#61; string&#10;    interfaces      &#61; list&#40;string&#41;&#10;  &#125;&#41;&#10;  tunnels &#61; list&#40;object&#40;&#123;&#10;    peer_asn                        &#61; number&#10;    peer_external_gateway_interface &#61; number&#10;    secret                          &#61; string&#10;    session_range                   &#61; string&#10;    vpn_gateway_interface           &#61; number&#10;  &#125;&#41;&#41;&#10;&#125;&#41;&#41;">map&#40;object&#40;&#123;&#8230;&#125;&#41;&#41;</code> |  | <code title="&#123;&#10;  landing-trusted-ew1 &#61; &#123;&#10;    adv &#61; &#123;&#10;      default &#61; false&#10;      custom &#61; &#91;&#10;        &#34;cloud_dns&#34;, &#34;googleapis_private&#34;, &#34;googleapis_restricted&#34;, &#34;gcp_all&#34;&#10;      &#93;&#10;    &#125;&#10;    peer_external_gateway &#61; &#123;&#10;      redundancy_type &#61; &#34;SINGLE_IP_INTERNALLY_REDUNDANT&#34;&#10;      interfaces      &#61; &#91;&#34;8.8.8.8&#34;&#93;&#10;    &#125;&#10;    tunnels &#61; &#91;&#10;      &#123;&#10;        peer_asn                        &#61; 65534&#10;        peer_external_gateway_interface &#61; 0&#10;        secret                          &#61; &#34;foobar&#34;&#10;        session_range                   &#61; &#34;169.254.1.0&#47;30&#34;&#10;        vpn_gateway_interface           &#61; 0&#10;      &#125;,&#10;      &#123;&#10;        peer_asn                        &#61; 65534&#10;        peer_external_gateway_interface &#61; 0&#10;        secret                          &#61; &#34;foobar&#34;&#10;        session_range                   &#61; &#34;169.254.1.4&#47;30&#34;&#10;        vpn_gateway_interface           &#61; 1&#10;      &#125;&#10;    &#93;&#10;  &#125;&#10;  landing-trusted-ew4 &#61; &#123;&#10;    adv &#61; &#123;&#10;      default &#61; false&#10;      custom &#61; &#91;&#10;        &#34;cloud_dns&#34;, &#34;googleapis_private&#34;, &#34;googleapis_restricted&#34;, &#34;gcp_all&#34;&#10;      &#93;&#10;    &#125;&#10;    peer_external_gateway &#61; &#123;&#10;      redundancy_type &#61; &#34;SINGLE_IP_INTERNALLY_REDUNDANT&#34;&#10;      interfaces      &#61; &#91;&#34;8.8.8.8&#34;&#93;&#10;    &#125;&#10;    tunnels &#61; &#91;&#10;      &#123;&#10;        peer_asn                        &#61; 65534&#10;        peer_external_gateway_interface &#61; 0&#10;        secret                          &#61; &#34;foobar&#34;&#10;        session_range                   &#61; &#34;169.254.1.0&#47;30&#34;&#10;        vpn_gateway_interface           &#61; 0&#10;      &#125;,&#10;      &#123;&#10;        peer_asn                        &#61; 65534&#10;        peer_external_gateway_interface &#61; 0&#10;        secret                          &#61; &#34;foobar&#34;&#10;        session_range                   &#61; &#34;169.254.1.4&#47;30&#34;&#10;        vpn_gateway_interface           &#61; 1&#10;      &#125;&#10;    &#93;&#10;  &#125;&#10;&#125;">&#123;&#8230;&#125;</code> |  |
 
 ## Outputs
 
diff --git a/fast/stages/02-networking-peering/README.md b/fast/stages/02-networking-peering/README.md
index f6a828099..c7829f0fb 100644
--- a/fast/stages/02-networking-peering/README.md
+++ b/fast/stages/02-networking-peering/README.md
@@ -311,7 +311,7 @@ DNS configurations are centralised in the `dns-*.tf` files. Spokes delegate DNS
 | [region_trigram](variables.tf#L166) | Short names for GCP regions. | <code>map&#40;string&#41;</code> |  | <code title="&#123;&#10;  europe-west1 &#61; &#34;ew1&#34;&#10;  europe-west3 &#61; &#34;ew3&#34;&#10;&#125;">&#123;&#8230;&#125;</code> |  |
 | [router_onprem_configs](variables.tf#L175) | Configurations for routers used for onprem connectivity. | <code title="map&#40;object&#40;&#123;&#10;  adv &#61; object&#40;&#123;&#10;    custom  &#61; list&#40;string&#41;&#10;    default &#61; bool&#10;  &#125;&#41;&#10;  asn &#61; number&#10;&#125;&#41;&#41;">map&#40;object&#40;&#123;&#8230;&#125;&#41;&#41;</code> |  | <code title="&#123;&#10;  landing-ew1 &#61; &#123;&#10;    asn &#61; &#34;65533&#34;&#10;    adv &#61; null&#10;  &#125;&#10;&#125;">&#123;&#8230;&#125;</code> |  |
 | [service_accounts](variables.tf#L193) | Automation service accounts in name => email format. | <code title="object&#40;&#123;&#10;  data-platform-dev    &#61; string&#10;  data-platform-prod   &#61; string&#10;  gke-dev              &#61; string&#10;  gke-prod             &#61; string&#10;  project-factory-dev  &#61; string&#10;  project-factory-prod &#61; string&#10;&#125;&#41;">object&#40;&#123;&#8230;&#125;&#41;</code> |  | <code>null</code> | <code>01-resman</code> |
-| [vpn_onprem_configs](variables.tf#L207) | VPN gateway configuration for onprem interconnection. | <code title="map&#40;object&#40;&#123;&#10;  adv &#61; object&#40;&#123;&#10;    default &#61; bool&#10;    custom  &#61; list&#40;string&#41;&#10;  &#125;&#41;&#10;  peer_external_gateway &#61; object&#40;&#123;&#10;    redundancy_type &#61; string&#10;    interfaces &#61; list&#40;object&#40;&#123;&#10;      id         &#61; number&#10;      ip_address &#61; string&#10;    &#125;&#41;&#41;&#10;  &#125;&#41;&#10;  tunnels &#61; list&#40;object&#40;&#123;&#10;    peer_asn                        &#61; number&#10;    peer_external_gateway_interface &#61; number&#10;    secret                          &#61; string&#10;    session_range                   &#61; string&#10;    vpn_gateway_interface           &#61; number&#10;  &#125;&#41;&#41;&#10;&#125;&#41;&#41;">map&#40;object&#40;&#123;&#8230;&#125;&#41;&#41;</code> |  | <code title="&#123;&#10;  landing-ew1 &#61; &#123;&#10;    adv &#61; &#123;&#10;      default &#61; false&#10;      custom &#61; &#91;&#10;        &#34;cloud_dns&#34;, &#34;googleapis_private&#34;, &#34;googleapis_restricted&#34;, &#34;gcp_all&#34;&#10;      &#93;&#10;    &#125;&#10;    peer_external_gateway &#61; &#123;&#10;      redundancy_type &#61; &#34;SINGLE_IP_INTERNALLY_REDUNDANT&#34;&#10;      interfaces &#61; &#91;&#10;        &#123; id &#61; 0, ip_address &#61; &#34;8.8.8.8&#34; &#125;,&#10;      &#93;&#10;    &#125;&#10;    tunnels &#61; &#91;&#10;      &#123;&#10;        peer_asn                        &#61; 65534&#10;        peer_external_gateway_interface &#61; 0&#10;        secret                          &#61; &#34;foobar&#34;&#10;        session_range                   &#61; &#34;169.254.1.0&#47;30&#34;&#10;        vpn_gateway_interface           &#61; 0&#10;      &#125;,&#10;      &#123;&#10;        peer_asn                        &#61; 65534&#10;        peer_external_gateway_interface &#61; 0&#10;        secret                          &#61; &#34;foobar&#34;&#10;        session_range                   &#61; &#34;169.254.1.4&#47;30&#34;&#10;        vpn_gateway_interface           &#61; 1&#10;      &#125;&#10;    &#93;&#10;  &#125;&#10;&#125;">&#123;&#8230;&#125;</code> |  |
+| [vpn_onprem_configs](variables.tf#L207) | VPN gateway configuration for onprem interconnection. | <code title="map&#40;object&#40;&#123;&#10;  adv &#61; object&#40;&#123;&#10;    default &#61; bool&#10;    custom  &#61; list&#40;string&#41;&#10;  &#125;&#41;&#10;  peer_external_gateway &#61; object&#40;&#123;&#10;    redundancy_type &#61; string&#10;    interfaces      &#61; list&#40;string&#41;&#10;  &#125;&#41;&#10;  tunnels &#61; list&#40;object&#40;&#123;&#10;    peer_asn                        &#61; number&#10;    peer_external_gateway_interface &#61; number&#10;    secret                          &#61; string&#10;    session_range                   &#61; string&#10;    vpn_gateway_interface           &#61; number&#10;  &#125;&#41;&#41;&#10;&#125;&#41;&#41;">map&#40;object&#40;&#123;&#8230;&#125;&#41;&#41;</code> |  | <code title="&#123;&#10;  landing-ew1 &#61; &#123;&#10;    adv &#61; &#123;&#10;      default &#61; false&#10;      custom &#61; &#91;&#10;        &#34;cloud_dns&#34;, &#34;googleapis_private&#34;, &#34;googleapis_restricted&#34;, &#34;gcp_all&#34;&#10;      &#93;&#10;    &#125;&#10;    peer_external_gateway &#61; &#123;&#10;      redundancy_type &#61; &#34;SINGLE_IP_INTERNALLY_REDUNDANT&#34;&#10;      interfaces      &#61; &#91;&#34;8.8.8.8&#34;&#93;&#10;    &#125;&#10;    tunnels &#61; &#91;&#10;      &#123;&#10;        peer_asn                        &#61; 65534&#10;        peer_external_gateway_interface &#61; 0&#10;        secret                          &#61; &#34;foobar&#34;&#10;        session_range                   &#61; &#34;169.254.1.0&#47;30&#34;&#10;        vpn_gateway_interface           &#61; 0&#10;      &#125;,&#10;      &#123;&#10;        peer_asn                        &#61; 65534&#10;        peer_external_gateway_interface &#61; 0&#10;        secret                          &#61; &#34;foobar&#34;&#10;        session_range                   &#61; &#34;169.254.1.4&#47;30&#34;&#10;        vpn_gateway_interface           &#61; 1&#10;      &#125;&#10;    &#93;&#10;  &#125;&#10;&#125;">&#123;&#8230;&#125;</code> |  |
 
 ## Outputs
 
diff --git a/fast/stages/02-networking-separate-envs/README.md b/fast/stages/02-networking-separate-envs/README.md
index a874311a9..66b31646e 100644
--- a/fast/stages/02-networking-separate-envs/README.md
+++ b/fast/stages/02-networking-separate-envs/README.md
@@ -252,7 +252,7 @@ You're now ready to run `terraform init` and `apply`.
 | [psa_ranges](variables.tf#L129) | IP ranges used for Private Service Access (e.g. CloudSQL). | <code title="object&#40;&#123;&#10;  dev &#61; object&#40;&#123;&#10;    ranges &#61; map&#40;string&#41;&#10;    routes &#61; object&#40;&#123;&#10;      export &#61; bool&#10;      import &#61; bool&#10;    &#125;&#41;&#10;  &#125;&#41;&#10;  prod &#61; object&#40;&#123;&#10;    ranges &#61; map&#40;string&#41;&#10;    routes &#61; object&#40;&#123;&#10;      export &#61; bool&#10;      import &#61; bool&#10;    &#125;&#41;&#10;  &#125;&#41;&#10;&#125;&#41;">object&#40;&#123;&#8230;&#125;&#41;</code> |  | <code>null</code> |  |
 | [router_onprem_configs](variables.tf#L166) | Configurations for routers used for onprem connectivity. | <code title="map&#40;object&#40;&#123;&#10;  adv &#61; object&#40;&#123;&#10;    custom  &#61; list&#40;string&#41;&#10;    default &#61; bool&#10;  &#125;&#41;&#10;  asn &#61; number&#10;&#125;&#41;&#41;">map&#40;object&#40;&#123;&#8230;&#125;&#41;&#41;</code> |  | <code title="&#123;&#10;  prod-ew1 &#61; &#123;&#10;    asn &#61; &#34;65533&#34;&#10;    adv &#61; null&#10;  &#125;&#10;  dev-ew1 &#61; &#123;&#10;    asn &#61; &#34;65534&#34;&#10;    adv &#61; null&#10;  &#125;&#10;&#125;">&#123;&#8230;&#125;</code> |  |
 | [service_accounts](variables.tf#L189) | Automation service accounts in name => email format. | <code title="object&#40;&#123;&#10;  data-platform-dev    &#61; string&#10;  data-platform-prod   &#61; string&#10;  project-factory-dev  &#61; string&#10;  project-factory-prod &#61; string&#10;&#125;&#41;">object&#40;&#123;&#8230;&#125;&#41;</code> |  | <code>null</code> | <code>01-resman</code> |
-| [vpn_onprem_configs](variables.tf#L201) | VPN gateway configuration for onprem interconnection. | <code title="map&#40;object&#40;&#123;&#10;  adv &#61; object&#40;&#123;&#10;    default &#61; bool&#10;    custom  &#61; list&#40;string&#41;&#10;  &#125;&#41;&#10;  peer_external_gateway &#61; object&#40;&#123;&#10;    redundancy_type &#61; string&#10;    interfaces &#61; list&#40;object&#40;&#123;&#10;      id         &#61; number&#10;      ip_address &#61; string&#10;    &#125;&#41;&#41;&#10;  &#125;&#41;&#10;  tunnels &#61; list&#40;object&#40;&#123;&#10;    peer_asn                        &#61; number&#10;    peer_external_gateway_interface &#61; number&#10;    secret                          &#61; string&#10;    session_range                   &#61; string&#10;    vpn_gateway_interface           &#61; number&#10;  &#125;&#41;&#41;&#10;&#125;&#41;&#41;">map&#40;object&#40;&#123;&#8230;&#125;&#41;&#41;</code> |  | <code title="&#123;&#10;  dev-ew1 &#61; &#123;&#10;    adv &#61; &#123;&#10;      default &#61; false&#10;      custom &#61; &#91;&#10;        &#34;cloud_dns&#34;, &#34;googleapis_private&#34;, &#34;googleapis_restricted&#34;, &#34;gcp_dev&#34;&#10;      &#93;&#10;    &#125;&#10;    peer_external_gateway &#61; &#123;&#10;      redundancy_type &#61; &#34;SINGLE_IP_INTERNALLY_REDUNDANT&#34;&#10;      interfaces &#61; &#91;&#10;        &#123; id &#61; 0, ip_address &#61; &#34;8.8.8.8&#34; &#125;,&#10;      &#93;&#10;    &#125;&#10;    tunnels &#61; &#91;&#10;      &#123;&#10;        peer_asn                        &#61; 65544&#10;        peer_external_gateway_interface &#61; 0&#10;        secret                          &#61; &#34;foobar&#34;&#10;        session_range                   &#61; &#34;169.254.1.0&#47;30&#34;&#10;        vpn_gateway_interface           &#61; 0&#10;      &#125;,&#10;      &#123;&#10;        peer_asn                        &#61; 65544&#10;        peer_external_gateway_interface &#61; 0&#10;        secret                          &#61; &#34;foobar&#34;&#10;        session_range                   &#61; &#34;169.254.1.4&#47;30&#34;&#10;        vpn_gateway_interface           &#61; 1&#10;      &#125;&#10;    &#93;&#10;  &#125;&#10;  prod-ew1 &#61; &#123;&#10;    adv &#61; &#123;&#10;      default &#61; false&#10;      custom &#61; &#91;&#10;        &#34;cloud_dns&#34;, &#34;googleapis_private&#34;, &#34;googleapis_restricted&#34;, &#34;gcp_prod&#34;&#10;      &#93;&#10;    &#125;&#10;    peer_external_gateway &#61; &#123;&#10;      redundancy_type &#61; &#34;SINGLE_IP_INTERNALLY_REDUNDANT&#34;&#10;      interfaces &#61; &#91;&#10;        &#123; id &#61; 0, ip_address &#61; &#34;8.8.8.8&#34; &#125;,&#10;      &#93;&#10;    &#125;&#10;    tunnels &#61; &#91;&#10;      &#123;&#10;        peer_asn                        &#61; 65543&#10;        peer_external_gateway_interface &#61; 0&#10;        secret                          &#61; &#34;foobar&#34;&#10;        session_range                   &#61; &#34;169.254.1.0&#47;30&#34;&#10;        vpn_gateway_interface           &#61; 0&#10;      &#125;,&#10;      &#123;&#10;        peer_asn                        &#61; 65543&#10;        peer_external_gateway_interface &#61; 0&#10;        secret                          &#61; &#34;foobar&#34;&#10;        session_range                   &#61; &#34;169.254.1.4&#47;30&#34;&#10;        vpn_gateway_interface           &#61; 1&#10;      &#125;&#10;    &#93;&#10;  &#125;&#10;&#125;">&#123;&#8230;&#125;</code> |  |
+| [vpn_onprem_configs](variables.tf#L201) | VPN gateway configuration for onprem interconnection. | <code title="map&#40;object&#40;&#123;&#10;  adv &#61; object&#40;&#123;&#10;    default &#61; bool&#10;    custom  &#61; list&#40;string&#41;&#10;  &#125;&#41;&#10;  peer_external_gateway &#61; object&#40;&#123;&#10;    redundancy_type &#61; string&#10;    interfaces      &#61; list&#40;string&#41;&#10;  &#125;&#41;&#10;  tunnels &#61; list&#40;object&#40;&#123;&#10;    peer_asn                        &#61; number&#10;    peer_external_gateway_interface &#61; number&#10;    secret                          &#61; string&#10;    session_range                   &#61; string&#10;    vpn_gateway_interface           &#61; number&#10;  &#125;&#41;&#41;&#10;&#125;&#41;&#41;">map&#40;object&#40;&#123;&#8230;&#125;&#41;&#41;</code> |  | <code title="&#123;&#10;  dev-ew1 &#61; &#123;&#10;    adv &#61; &#123;&#10;      default &#61; false&#10;      custom &#61; &#91;&#10;        &#34;cloud_dns&#34;, &#34;googleapis_private&#34;, &#34;googleapis_restricted&#34;, &#34;gcp_dev&#34;&#10;      &#93;&#10;    &#125;&#10;    peer_external_gateway &#61; &#123;&#10;      redundancy_type &#61; &#34;SINGLE_IP_INTERNALLY_REDUNDANT&#34;&#10;      interfaces      &#61; &#91;&#34;8.8.8.8&#34;&#93;&#10;&#10;&#10;    &#125;&#10;    tunnels &#61; &#91;&#10;      &#123;&#10;        peer_asn                        &#61; 65544&#10;        peer_external_gateway_interface &#61; 0&#10;        secret                          &#61; &#34;foobar&#34;&#10;        session_range                   &#61; &#34;169.254.1.0&#47;30&#34;&#10;        vpn_gateway_interface           &#61; 0&#10;      &#125;,&#10;      &#123;&#10;        peer_asn                        &#61; 65544&#10;        peer_external_gateway_interface &#61; 0&#10;        secret                          &#61; &#34;foobar&#34;&#10;        session_range                   &#61; &#34;169.254.1.4&#47;30&#34;&#10;        vpn_gateway_interface           &#61; 1&#10;      &#125;&#10;    &#93;&#10;  &#125;&#10;  prod-ew1 &#61; &#123;&#10;    adv &#61; &#123;&#10;      default &#61; false&#10;      custom &#61; &#91;&#10;        &#34;cloud_dns&#34;, &#34;googleapis_private&#34;, &#34;googleapis_restricted&#34;, &#34;gcp_prod&#34;&#10;      &#93;&#10;    &#125;&#10;    peer_external_gateway &#61; &#123;&#10;      redundancy_type &#61; &#34;SINGLE_IP_INTERNALLY_REDUNDANT&#34;&#10;      interfaces      &#61; &#91;&#34;8.8.8.8&#34;&#93;&#10;    &#125;&#10;    tunnels &#61; &#91;&#10;      &#123;&#10;        peer_asn                        &#61; 65543&#10;        peer_external_gateway_interface &#61; 0&#10;        secret                          &#61; &#34;foobar&#34;&#10;        session_range                   &#61; &#34;169.254.1.0&#47;30&#34;&#10;        vpn_gateway_interface           &#61; 0&#10;      &#125;,&#10;      &#123;&#10;        peer_asn                        &#61; 65543&#10;        peer_external_gateway_interface &#61; 0&#10;        secret                          &#61; &#34;foobar&#34;&#10;        session_range                   &#61; &#34;169.254.1.4&#47;30&#34;&#10;        vpn_gateway_interface           &#61; 1&#10;      &#125;&#10;    &#93;&#10;  &#125;&#10;&#125;">&#123;&#8230;&#125;</code> |  |
 
 ## Outputs
 
diff --git a/fast/stages/02-networking-vpn/README.md b/fast/stages/02-networking-vpn/README.md
index 8a884c09b..047a1189c 100644
--- a/fast/stages/02-networking-vpn/README.md
+++ b/fast/stages/02-networking-vpn/README.md
@@ -336,7 +336,7 @@ DNS configurations are centralised in the `dns-*.tf` files. Spokes delegate DNS
 | [router_onprem_configs](variables.tf#L175) | Configurations for routers used for onprem connectivity. | <code title="map&#40;object&#40;&#123;&#10;  adv &#61; object&#40;&#123;&#10;    custom  &#61; list&#40;string&#41;&#10;    default &#61; bool&#10;  &#125;&#41;&#10;  asn &#61; number&#10;&#125;&#41;&#41;">map&#40;object&#40;&#123;&#8230;&#125;&#41;&#41;</code> |  | <code title="&#123;&#10;  landing-ew1 &#61; &#123;&#10;    asn &#61; &#34;65533&#34;&#10;    adv &#61; null&#10;  &#125;&#10;&#125;">&#123;&#8230;&#125;</code> |  |
 | [router_spoke_configs](variables-vpn.tf#L18) | Configurations for routers used for internal connectivity. | <code title="map&#40;object&#40;&#123;&#10;  adv &#61; object&#40;&#123;&#10;    custom  &#61; list&#40;string&#41;&#10;    default &#61; bool&#10;  &#125;&#41;&#10;  asn &#61; number&#10;&#125;&#41;&#41;">map&#40;object&#40;&#123;&#8230;&#125;&#41;&#41;</code> |  | <code title="&#123;&#10;  landing-ew1    &#61; &#123; asn &#61; &#34;64512&#34;, adv &#61; null &#125;&#10;  landing-ew4    &#61; &#123; asn &#61; &#34;64512&#34;, adv &#61; null &#125;&#10;  spoke-dev-ew1  &#61; &#123; asn &#61; &#34;64513&#34;, adv &#61; null &#125;&#10;  spoke-dev-ew4  &#61; &#123; asn &#61; &#34;64513&#34;, adv &#61; null &#125;&#10;  spoke-prod-ew1 &#61; &#123; asn &#61; &#34;64514&#34;, adv &#61; null &#125;&#10;  spoke-prod-ew4 &#61; &#123; asn &#61; &#34;64514&#34;, adv &#61; null &#125;&#10;&#125;">&#123;&#8230;&#125;</code> |  |
 | [service_accounts](variables.tf#L193) | Automation service accounts in name => email format. | <code title="object&#40;&#123;&#10;  data-platform-dev    &#61; string&#10;  data-platform-prod   &#61; string&#10;  gke-dev              &#61; string&#10;  gke-prod             &#61; string&#10;  project-factory-dev  &#61; string&#10;  project-factory-prod &#61; string&#10;&#125;&#41;">object&#40;&#123;&#8230;&#125;&#41;</code> |  | <code>null</code> | <code>01-resman</code> |
-| [vpn_onprem_configs](variables.tf#L207) | VPN gateway configuration for onprem interconnection. | <code title="map&#40;object&#40;&#123;&#10;  adv &#61; object&#40;&#123;&#10;    default &#61; bool&#10;    custom  &#61; list&#40;string&#41;&#10;  &#125;&#41;&#10;  peer_external_gateway &#61; object&#40;&#123;&#10;    redundancy_type &#61; string&#10;    interfaces &#61; list&#40;object&#40;&#123;&#10;      id         &#61; number&#10;      ip_address &#61; string&#10;    &#125;&#41;&#41;&#10;  &#125;&#41;&#10;  tunnels &#61; list&#40;object&#40;&#123;&#10;    peer_asn                        &#61; number&#10;    peer_external_gateway_interface &#61; number&#10;    secret                          &#61; string&#10;    session_range                   &#61; string&#10;    vpn_gateway_interface           &#61; number&#10;  &#125;&#41;&#41;&#10;&#125;&#41;&#41;">map&#40;object&#40;&#123;&#8230;&#125;&#41;&#41;</code> |  | <code title="&#123;&#10;  landing-ew1 &#61; &#123;&#10;    adv &#61; &#123;&#10;      default &#61; false&#10;      custom &#61; &#91;&#10;        &#34;cloud_dns&#34;, &#34;googleapis_private&#34;, &#34;googleapis_restricted&#34;, &#34;gcp_all&#34;&#10;      &#93;&#10;    &#125;&#10;    peer_external_gateway &#61; &#123;&#10;      redundancy_type &#61; &#34;SINGLE_IP_INTERNALLY_REDUNDANT&#34;&#10;      interfaces &#61; &#91;&#10;        &#123; id &#61; 0, ip_address &#61; &#34;8.8.8.8&#34; &#125;,&#10;      &#93;&#10;    &#125;&#10;    tunnels &#61; &#91;&#10;      &#123;&#10;        peer_asn                        &#61; 65534&#10;        peer_external_gateway_interface &#61; 0&#10;        secret                          &#61; &#34;foobar&#34;&#10;        session_range                   &#61; &#34;169.254.1.0&#47;30&#34;&#10;        vpn_gateway_interface           &#61; 0&#10;      &#125;,&#10;      &#123;&#10;        peer_asn                        &#61; 65534&#10;        peer_external_gateway_interface &#61; 0&#10;        secret                          &#61; &#34;foobar&#34;&#10;        session_range                   &#61; &#34;169.254.1.4&#47;30&#34;&#10;        vpn_gateway_interface           &#61; 1&#10;      &#125;&#10;    &#93;&#10;  &#125;&#10;&#125;">&#123;&#8230;&#125;</code> |  |
+| [vpn_onprem_configs](variables.tf#L207) | VPN gateway configuration for onprem interconnection. | <code title="map&#40;object&#40;&#123;&#10;  adv &#61; object&#40;&#123;&#10;    default &#61; bool&#10;    custom  &#61; list&#40;string&#41;&#10;  &#125;&#41;&#10;  peer_external_gateway &#61; object&#40;&#123;&#10;    redundancy_type &#61; string&#10;    interfaces      &#61; list&#40;string&#41;&#10;  &#125;&#41;&#10;  tunnels &#61; list&#40;object&#40;&#123;&#10;    peer_asn                        &#61; number&#10;    peer_external_gateway_interface &#61; number&#10;    secret                          &#61; string&#10;    session_range                   &#61; string&#10;    vpn_gateway_interface           &#61; number&#10;  &#125;&#41;&#41;&#10;&#125;&#41;&#41;">map&#40;object&#40;&#123;&#8230;&#125;&#41;&#41;</code> |  | <code title="&#123;&#10;  landing-ew1 &#61; &#123;&#10;    adv &#61; &#123;&#10;      default &#61; false&#10;      custom &#61; &#91;&#10;        &#34;cloud_dns&#34;, &#34;googleapis_private&#34;, &#34;googleapis_restricted&#34;, &#34;gcp_all&#34;&#10;      &#93;&#10;    &#125;&#10;    peer_external_gateway &#61; &#123;&#10;      redundancy_type &#61; &#34;SINGLE_IP_INTERNALLY_REDUNDANT&#34;&#10;      interfaces      &#61; &#91;&#34;8.8.8.8&#34;&#93;&#10;    &#125;&#10;    tunnels &#61; &#91;&#10;      &#123;&#10;        peer_asn                        &#61; 65534&#10;        peer_external_gateway_interface &#61; 0&#10;        secret                          &#61; &#34;foobar&#34;&#10;        session_range                   &#61; &#34;169.254.1.0&#47;30&#34;&#10;        vpn_gateway_interface           &#61; 0&#10;      &#125;,&#10;      &#123;&#10;        peer_asn                        &#61; 65534&#10;        peer_external_gateway_interface &#61; 0&#10;        secret                          &#61; &#34;foobar&#34;&#10;        session_range                   &#61; &#34;169.254.1.4&#47;30&#34;&#10;        vpn_gateway_interface           &#61; 1&#10;      &#125;&#10;    &#93;&#10;  &#125;&#10;&#125;">&#123;&#8230;&#125;</code> |  |
 | [vpn_spoke_configs](variables-vpn.tf#L37) | VPN gateway configuration for spokes. | <code title="map&#40;object&#40;&#123;&#10;  default &#61; bool&#10;  custom  &#61; list&#40;string&#41;&#10;&#125;&#41;&#41;">map&#40;object&#40;&#123;&#8230;&#125;&#41;&#41;</code> |  | <code title="&#123;&#10;  landing-ew1 &#61; &#123;&#10;    default &#61; false&#10;    custom  &#61; &#91;&#34;rfc_1918_10&#34;, &#34;rfc_1918_172&#34;, &#34;rfc_1918_192&#34;&#93;&#10;  &#125;&#10;  landing-ew4 &#61; &#123;&#10;    default &#61; false&#10;    custom  &#61; &#91;&#34;rfc_1918_10&#34;, &#34;rfc_1918_172&#34;, &#34;rfc_1918_192&#34;&#93;&#10;  &#125;&#10;  dev-ew1 &#61; &#123;&#10;    default &#61; false&#10;    custom  &#61; &#91;&#34;gcp_dev&#34;&#93;&#10;  &#125;&#10;  prod-ew1 &#61; &#123;&#10;    default &#61; false&#10;    custom  &#61; &#91;&#34;gcp_prod&#34;&#93;&#10;  &#125;&#10;  prod-ew4 &#61; &#123;&#10;    default &#61; false&#10;    custom  &#61; &#91;&#34;gcp_prod&#34;&#93;&#10;  &#125;&#10;&#125;">&#123;&#8230;&#125;</code> |  |
 
 ## Outputs
diff --git a/modules/net-vpn-ha/README.md b/modules/net-vpn-ha/README.md
index be09a8e06..1c1a23ce2 100644
--- a/modules/net-vpn-ha/README.md
+++ b/modules/net-vpn-ha/README.md
@@ -126,18 +126,12 @@ module "vpn_ha" {
 |---|---|:---:|:---:|:---:|
 | [name](variables.tf#L17) | VPN Gateway name (if an existing VPN Gateway is not used), and prefix used for dependent resources. | <code>string</code> | ✓ |  |
 | [network](variables.tf#L22) | VPC used for the gateway and routes. | <code>string</code> | ✓ |  |
-| [project_id](variables.tf#L45) | Project where resources will be created. | <code>string</code> | ✓ |  |
-| [region](variables.tf#L50) | Region used for resources. | <code>string</code> | ✓ |  |
-| [peer_external_gateway](variables.tf#L27) | Configuration of an external VPN gateway to which this VPN is connected. | <code title="object&#40;&#123;&#10;  redundancy_type &#61; string&#10;  interfaces &#61; list&#40;object&#40;&#123;&#10;    id         &#61; number&#10;    ip_address &#61; string&#10;  &#125;&#41;&#41;&#10;&#125;&#41;">object&#40;&#123;&#8230;&#125;&#41;</code> |  | <code>null</code> |
-| [peer_gcp_gateway](variables.tf#L39) | Self Link URL of the peer side HA GCP VPN gateway to which this VPN tunnel is connected. | <code>string</code> |  | <code>null</code> |
-| [route_priority](variables.tf#L55) | Route priority, defaults to 1000. | <code>number</code> |  | <code>1000</code> |
-| [router_advertise_config](variables.tf#L61) | Router custom advertisement configuration, ip_ranges is a map of address ranges and descriptions. | <code title="object&#40;&#123;&#10;  groups    &#61; list&#40;string&#41;&#10;  ip_ranges &#61; map&#40;string&#41;&#10;  mode      &#61; string&#10;&#125;&#41;">object&#40;&#123;&#8230;&#125;&#41;</code> |  | <code>null</code> |
-| [router_asn](variables.tf#L71) | Router ASN used for auto-created router. | <code>number</code> |  | <code>64514</code> |
-| [router_create](variables.tf#L77) | Create router. | <code>bool</code> |  | <code>true</code> |
-| [router_name](variables.tf#L83) | Router name used for auto created router, or to specify an existing router to use if `router_create` is set to `true`. Leave blank to use VPN name for auto created router. | <code>string</code> |  | <code>&#34;&#34;</code> |
-| [tunnels](variables.tf#L89) | VPN tunnel configurations, bgp_peer_options is usually null. | <code title="map&#40;object&#40;&#123;&#10;  bgp_peer &#61; object&#40;&#123;&#10;    address &#61; string&#10;    asn     &#61; number&#10;  &#125;&#41;&#10;  bgp_peer_options &#61; object&#40;&#123;&#10;    advertise_groups    &#61; list&#40;string&#41;&#10;    advertise_ip_ranges &#61; map&#40;string&#41;&#10;    advertise_mode      &#61; string&#10;    route_priority      &#61; number&#10;  &#125;&#41;&#10;  bgp_session_range               &#61; string&#10;  ike_version                     &#61; number&#10;  peer_external_gateway_interface &#61; number&#10;  router                          &#61; string&#10;  shared_secret                   &#61; string&#10;  vpn_gateway_interface           &#61; number&#10;&#125;&#41;&#41;">map&#40;object&#40;&#123;&#8230;&#125;&#41;&#41;</code> |  | <code>&#123;&#125;</code> |
-| [vpn_gateway](variables.tf#L114) | HA VPN Gateway Self Link for using an existing HA VPN Gateway, leave empty if `vpn_gateway_create` is set to `true`. | <code>string</code> |  | <code>null</code> |
-| [vpn_gateway_create](variables.tf#L120) | Create HA VPN Gateway. | <code>bool</code> |  | <code>true</code> |
+| [peer_gateway](variables.tf#L27) | Configuration of the (external or GCP) peer gateway. | <code title="object&#40;&#123;&#10;  external &#61; optional&#40;object&#40;&#123;&#10;    redundancy_type &#61; string&#10;    interfaces      &#61; list&#40;string&#41;&#10;  &#125;&#41;&#41;&#10;  gcp &#61; optional&#40;string&#41;&#10;&#125;&#41;">object&#40;&#123;&#8230;&#125;&#41;</code> | ✓ |  |
+| [project_id](variables.tf#L43) | Project where resources will be created. | <code>string</code> | ✓ |  |
+| [region](variables.tf#L48) | Region used for resources. | <code>string</code> | ✓ |  |
+| [router_config](variables.tf#L53) | Cloud Router configuration for the VPN. If you want to reuse an existing router, set create to false and use name to specify the desired router. | <code title="object&#40;&#123;&#10;  create    &#61; optional&#40;bool, true&#41;&#10;  asn       &#61; number&#10;  name      &#61; optional&#40;string&#41;&#10;  keepalive &#61; optional&#40;number&#41;&#10;  custom_advertise &#61; optional&#40;object&#40;&#123;&#10;    all_subnets &#61; bool&#10;    ip_ranges   &#61; map&#40;string&#41;&#10;  &#125;&#41;&#41;&#10;&#125;&#41;">object&#40;&#123;&#8230;&#125;&#41;</code> | ✓ |  |
+| [tunnels](variables.tf#L68) | VPN tunnel configurations, bgp_peer_options is usually null. | <code title="map&#40;object&#40;&#123;&#10;  bgp_peer &#61; object&#40;&#123;&#10;    address        &#61; string&#10;    asn            &#61; number&#10;    route_priority &#61; optional&#40;number, 1000&#41;&#10;    custom_advertise &#61; optional&#40;object&#40;&#123;&#10;      all_subnets          &#61; bool&#10;      all_vpc_subnets      &#61; bool&#10;      all_peer_vpc_subnets &#61; bool&#10;      ip_ranges            &#61; map&#40;string&#41;&#10;    &#125;&#41;&#41;&#10;  &#125;&#41;&#10;  bgp_session_range               &#61; string&#10;  ike_version                     &#61; optional&#40;number, 2&#41;&#10;  peer_external_gateway_interface &#61; optional&#40;number&#41;&#10;  router                          &#61; optional&#40;string&#41;&#10;  shared_secret                   &#61; optional&#40;string&#41;&#10;  vpn_gateway_interface           &#61; number&#10;&#125;&#41;&#41;">map&#40;object&#40;&#123;&#8230;&#125;&#41;&#41;</code> |  | <code>&#123;&#125;</code> |
+| [vpn_gateway](variables.tf#L95) | Self link of an existing HA VPN Gateway to use. Set to null to create new VPN Gateway. | <code>string</code> |  | <code>null</code> |
 
 ## Outputs
 
@@ -145,14 +139,14 @@ module "vpn_ha" {
 |---|---|:---:|
 | [bgp_peers](outputs.tf#L18) | BGP peer resources. |  |
 | [external_gateway](outputs.tf#L25) | External VPN gateway resource. |  |
-| [gateway](outputs.tf#L34) | VPN gateway resource (only if auto-created). |  |
-| [name](outputs.tf#L43) | VPN gateway name (only if auto-created). . |  |
-| [random_secret](outputs.tf#L52) | Generated secret. |  |
-| [router](outputs.tf#L57) | Router resource (only if auto-created). |  |
-| [router_name](outputs.tf#L66) | Router name. |  |
-| [self_link](outputs.tf#L71) | HA VPN gateway self link. |  |
-| [tunnel_names](outputs.tf#L76) | VPN tunnel names. |  |
-| [tunnel_self_links](outputs.tf#L84) | VPN tunnel self links. |  |
-| [tunnels](outputs.tf#L92) | VPN tunnel resources. |  |
+| [gateway](outputs.tf#L30) | VPN gateway resource (only if auto-created). |  |
+| [name](outputs.tf#L35) | VPN gateway name (only if auto-created). . |  |
+| [random_secret](outputs.tf#L40) | Generated secret. |  |
+| [router](outputs.tf#L45) | Router resource (only if auto-created). |  |
+| [router_name](outputs.tf#L50) | Router name. |  |
+| [self_link](outputs.tf#L55) | HA VPN gateway self link. |  |
+| [tunnel_names](outputs.tf#L60) | VPN tunnel names. |  |
+| [tunnel_self_links](outputs.tf#L68) | VPN tunnel self links. |  |
+| [tunnels](outputs.tf#L76) | VPN tunnel resources. |  |
 
 <!-- END TFDOC -->
diff --git a/modules/net-vpn-ha/variables.tf b/modules/net-vpn-ha/variables.tf
index 8f24b6cbc..f8ecd151f 100644
--- a/modules/net-vpn-ha/variables.tf
+++ b/modules/net-vpn-ha/variables.tf
@@ -25,6 +25,7 @@ variable "network" {
 }
 
 variable "peer_gateway" {
+  description = "Configuration of the (external or GCP) peer gateway."
   type = object({
     external = optional(object({
       redundancy_type = string
@@ -34,8 +35,8 @@ variable "peer_gateway" {
   })
   nullable = false
   validation {
-    condition     = var.peer_gateway.external != null || var.peer_gateway.gcp != null
-    error_message = "TODO"
+    condition     = (var.peer_gateway.external != null) != (var.peer_gateway.gcp != null)
+    error_message = "Peer gateway configuration must define exactly one between `external` and `gcp`."
   }
 }
 
@@ -50,6 +51,7 @@ variable "region" {
 }
 
 variable "router_config" {
+  description = "Cloud Router configuration for the VPN. If you want to reuse an existing router, set create to false and use name to specify the desired router."
   type = object({
     create    = optional(bool, true)
     asn       = number