diff --git a/e2e_tests/test_performance.py b/e2e_tests/test_performance.py
index f6e7637fe..7fa0208a7 100644
--- a/e2e_tests/test_performance.py
+++ b/e2e_tests/test_performance.py
@@ -106,7 +106,8 @@ async def test_bulk_updates_to_ensure_each_resource_updated_in_series(verify) ->
         "properties": {
             "display_name": "Perf test VM",
             "description": "",
-            "os_image": "Ubuntu 22.04 LTS"
+            "os_image": "Ubuntu 22.04 LTS",
+            "admin_username": "researcher"
         }
     }
 
diff --git a/e2e_tests/test_workspace_services.py b/e2e_tests/test_workspace_services.py
index 3013fef37..c4b67036a 100644
--- a/e2e_tests/test_workspace_services.py
+++ b/e2e_tests/test_workspace_services.py
@@ -31,7 +31,8 @@ async def test_create_guacamole_service_into_base_workspace(setup_test_workspace
         "properties": {
             "display_name": "My VM",
             "description": "Will be using this VM for my research",
-            "os_image": "Windows 10"
+            "os_image": "Windows 10",
+            "admin_username": "researcher"
         }
     }
 
diff --git a/templates/workspace_services/guacamole/user_resources/guacamole-azure-linuxvm/porter.yaml b/templates/workspace_services/guacamole/user_resources/guacamole-azure-linuxvm/porter.yaml
index a8e04193e..7ebb8bccb 100644
--- a/templates/workspace_services/guacamole/user_resources/guacamole-azure-linuxvm/porter.yaml
+++ b/templates/workspace_services/guacamole/user_resources/guacamole-azure-linuxvm/porter.yaml
@@ -108,6 +108,9 @@ parameters:
   - name: os_image
     type: string
     default: "Ubuntu 22.04 LTS"
+  - name: admin_username
+    type: string
+    default: ""
   - name: vm_size
     type: string
     default: "2 CPU | 8GB RAM"
@@ -166,6 +169,7 @@ install:
         parent_service_id: ${ bundle.parameters.parent_service_id }
         tre_resource_id: ${ bundle.parameters.id }
         image: ${ bundle.parameters.os_image }
+        admin_username: ${ bundle.parameters.admin_username }
         vm_size: ${ bundle.parameters.vm_size }
         shared_storage_access: ${ bundle.parameters.shared_storage_access }
         shared_storage_name: ${ bundle.parameters.shared_storage_name }
@@ -201,6 +205,7 @@ upgrade:
         parent_service_id: ${ bundle.parameters.parent_service_id }
         tre_resource_id: ${ bundle.parameters.id }
         image: ${ bundle.parameters.os_image }
+        admin_username: ${ bundle.parameters.admin_username }
         vm_size: ${ bundle.parameters.vm_size }
         shared_storage_access: ${ bundle.parameters.shared_storage_access }
         shared_storage_name: ${ bundle.parameters.shared_storage_name }
@@ -248,6 +253,7 @@ uninstall:
         parent_service_id: ${ bundle.parameters.parent_service_id }
         tre_resource_id: ${ bundle.parameters.id }
         image: ${ bundle.parameters.os_image }
+        admin_username: ${ bundle.parameters.admin_username }
         vm_size: ${ bundle.parameters.vm_size }
         shared_storage_access: ${ bundle.parameters.shared_storage_access }
         shared_storage_name: ${ bundle.parameters.shared_storage_name }
diff --git a/templates/workspace_services/guacamole/user_resources/guacamole-azure-linuxvm/template_schema.json b/templates/workspace_services/guacamole/user_resources/guacamole-azure-linuxvm/template_schema.json
index aa0066883..7e1afc80a 100644
--- a/templates/workspace_services/guacamole/user_resources/guacamole-azure-linuxvm/template_schema.json
+++ b/templates/workspace_services/guacamole/user_resources/guacamole-azure-linuxvm/template_schema.json
@@ -36,6 +36,12 @@
         "Ubuntu 22.04 LTS"
       ]
     },
+    "admin_username": {
+      "type": "string",
+      "title": "Admin username",
+      "description": "Overide automatic admin username generation.",
+      "default": ""
+    },
     "vm_size": {
       "$id": "#/properties/vm_size",
       "type": "string",
@@ -126,5 +132,10 @@
         ]
       }
     }
-  ]
+  ],
+  "uiSchema": {
+    "admin_username": {
+      "classNames": "tre-hidden"
+    }
+  }
 }
diff --git a/templates/workspace_services/guacamole/user_resources/guacamole-azure-linuxvm/terraform/data.tf b/templates/workspace_services/guacamole/user_resources/guacamole-azure-linuxvm/terraform/data.tf
index 507047663..3e0cfb10d 100644
--- a/templates/workspace_services/guacamole/user_resources/guacamole-azure-linuxvm/terraform/data.tf
+++ b/templates/workspace_services/guacamole/user_resources/guacamole-azure-linuxvm/terraform/data.tf
@@ -72,5 +72,6 @@ data "azurerm_storage_account" "stg" {
 }
 
 data "azuread_user" "user" {
+  count     = var.admin_username == "" ? 1 : 0
   object_id = var.owner_id
 }
diff --git a/templates/workspace_services/guacamole/user_resources/guacamole-azure-linuxvm/terraform/locals.tf b/templates/workspace_services/guacamole/user_resources/guacamole-azure-linuxvm/terraform/locals.tf
index c304adb75..abc5f4307 100644
--- a/templates/workspace_services/guacamole/user_resources/guacamole-azure-linuxvm/terraform/locals.tf
+++ b/templates/workspace_services/guacamole/user_resources/guacamole-azure-linuxvm/terraform/locals.tf
@@ -8,9 +8,12 @@ locals {
   keyvault_name                  = lower("kv-${substr(local.workspace_resource_name_suffix, -20, -1)}")
   storage_name                   = lower(replace("stg${substr(local.workspace_resource_name_suffix, -8, -1)}", "-", ""))
   admin_username = (
-    length(data.azuread_user.user.mail) > 0 && strcontains(data.azuread_user.user.user_principal_name, "#EXT#") ?
-    substr(element(split("@", data.azuread_user.user.mail), 0), 0, 20) :
-    substr(element(split("#EXT#", element(split("@", data.azuread_user.user.user_principal_name), 0)), 0), 0, 20)
+    var.admin_username == "" ?
+    (length(data.azuread_user.user[0].mail) > 0 && strcontains(data.azuread_user.user[0].user_principal_name, "#EXT#") ?
+      substr(element(split("@", data.azuread_user.user[0].mail), 0), 0, 20) :
+      substr(element(split("#EXT#", element(split("@", data.azuread_user.user[0].user_principal_name), 0)), 0), 0, 20)
+    ) :
+    var.admin_username
   )
   vm_password_secret_name = "${local.vm_name}-admin-credentials"
   tre_user_resources_tags = {
@@ -19,7 +22,7 @@ locals {
     tre_workspace_service_id = var.parent_service_id
     tre_user_resource_id     = var.tre_resource_id
     tre_user_id              = var.owner_id
-    tre_user_username        = data.azuread_user.user.user_principal_name
+    tre_user_username        = var.admin_username == "" ? local.admin_username : var.admin_username
   }
   nexus_proxy_url = "https://nexus-${data.azurerm_public_ip.app_gateway_ip.fqdn}"
   # Load VM SKU/image details from porter.yaml
diff --git a/templates/workspace_services/guacamole/user_resources/guacamole-azure-linuxvm/terraform/variables.tf b/templates/workspace_services/guacamole/user_resources/guacamole-azure-linuxvm/terraform/variables.tf
index 8546da7b9..bb80e979b 100644
--- a/templates/workspace_services/guacamole/user_resources/guacamole-azure-linuxvm/terraform/variables.tf
+++ b/templates/workspace_services/guacamole/user_resources/guacamole-azure-linuxvm/terraform/variables.tf
@@ -48,14 +48,14 @@ variable "key_store_id" {
   type = string
 }
 variable "auth_tenant_id" {
-  type        = string
-  description = "Used to authenticate into the AAD Tenant to create the AAD App"
+  type = string
 }
 variable "auth_client_id" {
-  type        = string
-  description = "Used to authenticate into the AAD Tenant to create the AAD App"
+  type = string
 }
 variable "auth_client_secret" {
-  type        = string
-  description = "Used to authenticate into the AAD Tenant to create the AAD App"
+  type = string
+}
+variable "admin_username" {
+  type = string
 }
diff --git a/templates/workspace_services/guacamole/user_resources/guacamole-azure-windowsvm/porter.yaml b/templates/workspace_services/guacamole/user_resources/guacamole-azure-windowsvm/porter.yaml
index 79c06e529..153cf482b 100644
--- a/templates/workspace_services/guacamole/user_resources/guacamole-azure-windowsvm/porter.yaml
+++ b/templates/workspace_services/guacamole/user_resources/guacamole-azure-windowsvm/porter.yaml
@@ -1,7 +1,7 @@
 ---
 schemaVersion: 1.0.0
 name: tre-service-guacamole-windowsvm
-version: 1.2.10
+version: 1.2.14
 description: "An Azure TRE User Resource Template for Guacamole (Windows 10)"
 dockerfile: Dockerfile.tmpl
 registry: azuretre
@@ -104,6 +104,9 @@ parameters:
   - name: os_image
     type: string
     default: "Windows 10"
+  - name: admin_username
+    type: string
+    default: ""
   - name: vm_size
     type: string
     default: "2 CPU | 8GB RAM"
@@ -164,6 +167,7 @@ install:
         parent_service_id: ${ bundle.parameters.parent_service_id }
         tre_resource_id: ${ bundle.parameters.id }
         image: ${ bundle.parameters.os_image }
+        admin_username: ${ bundle.parameters.admin_username }
         vm_size: ${ bundle.parameters.vm_size }
         shared_storage_access: ${ bundle.parameters.shared_storage_access }
         shared_storage_name: ${ bundle.parameters.shared_storage_name }
@@ -196,6 +200,7 @@ upgrade:
         parent_service_id: ${ bundle.parameters.parent_service_id }
         tre_resource_id: ${ bundle.parameters.id }
         image: ${ bundle.parameters.os_image }
+        admin_username: ${ bundle.parameters.admin_username }
         vm_size: ${ bundle.parameters.vm_size }
         shared_storage_access: ${ bundle.parameters.shared_storage_access }
         shared_storage_name: ${ bundle.parameters.shared_storage_name }
@@ -240,6 +245,7 @@ uninstall:
         parent_service_id: ${ bundle.parameters.parent_service_id }
         tre_resource_id: ${ bundle.parameters.id }
         image: ${ bundle.parameters.os_image }
+        admin_username: ${ bundle.parameters.admin_username }
         vm_size: ${ bundle.parameters.vm_size }
         shared_storage_access: ${ bundle.parameters.shared_storage_access }
         shared_storage_name: ${ bundle.parameters.shared_storage_name }
diff --git a/templates/workspace_services/guacamole/user_resources/guacamole-azure-windowsvm/template_schema.json b/templates/workspace_services/guacamole/user_resources/guacamole-azure-windowsvm/template_schema.json
index 477f88cef..8d1525be0 100644
--- a/templates/workspace_services/guacamole/user_resources/guacamole-azure-windowsvm/template_schema.json
+++ b/templates/workspace_services/guacamole/user_resources/guacamole-azure-windowsvm/template_schema.json
@@ -36,6 +36,12 @@
           "Server 2019 Data Science VM"
         ]
       },
+      "admin_username": {
+        "type": "string",
+        "title": "Admin username",
+        "description": "Overide automatic admin username generation.",
+        "default": ""
+      },
       "vm_size": {
         "$id": "#/properties/vm_size",
         "type": "string",
@@ -57,5 +63,10 @@
         "default": true,
         "description": "Enable access to shared storage"
       }
+    },
+    "uiSchema": {
+      "admin_username": {
+        "classNames": "tre-hidden"
+      }
     }
 }
diff --git a/templates/workspace_services/guacamole/user_resources/guacamole-azure-windowsvm/terraform/data.tf b/templates/workspace_services/guacamole/user_resources/guacamole-azure-windowsvm/terraform/data.tf
index 968e8d9bc..b83045c0a 100644
--- a/templates/workspace_services/guacamole/user_resources/guacamole-azure-windowsvm/terraform/data.tf
+++ b/templates/workspace_services/guacamole/user_resources/guacamole-azure-windowsvm/terraform/data.tf
@@ -50,5 +50,6 @@ data "azurerm_user_assigned_identity" "ws_encryption_identity" {
 }
 
 data "azuread_user" "user" {
+  count     = var.admin_username == "" ? 1 : 0
   object_id = var.owner_id
 }
diff --git a/templates/workspace_services/guacamole/user_resources/guacamole-azure-windowsvm/terraform/locals.tf b/templates/workspace_services/guacamole/user_resources/guacamole-azure-windowsvm/terraform/locals.tf
index 713db2d05..3590a2b73 100644
--- a/templates/workspace_services/guacamole/user_resources/guacamole-azure-windowsvm/terraform/locals.tf
+++ b/templates/workspace_services/guacamole/user_resources/guacamole-azure-windowsvm/terraform/locals.tf
@@ -8,9 +8,12 @@ locals {
   keyvault_name                  = lower("kv-${substr(local.workspace_resource_name_suffix, -20, -1)}")
   storage_name                   = lower(replace("stg${substr(local.workspace_resource_name_suffix, -8, -1)}", "-", ""))
   admin_username = (
-    length(data.azuread_user.user.mail) > 0 && strcontains(data.azuread_user.user.user_principal_name, "#EXT#") ?
-    substr(element(split("@", data.azuread_user.user.mail), 0), 0, 20) :
-    substr(element(split("#EXT#", element(split("@", data.azuread_user.user.user_principal_name), 0)), 0), 0, 20)
+    var.admin_username == "" ?
+    (length(data.azuread_user.user[0].mail) > 0 && strcontains(data.azuread_user.user[0].user_principal_name, "#EXT#") ?
+      substr(element(split("@", data.azuread_user.user[0].mail), 0), 0, 20) :
+      substr(element(split("#EXT#", element(split("@", data.azuread_user.user[0].user_principal_name), 0)), 0), 0, 20)
+    ) :
+    var.admin_username
   )
   vm_password_secret_name = "${local.vm_name}-admin-credentials"
   tre_user_resources_tags = {
@@ -19,7 +22,7 @@ locals {
     tre_workspace_service_id = var.parent_service_id
     tre_user_resource_id     = var.tre_resource_id
     tre_user_id              = var.owner_id
-    tre_user_username        = data.azuread_user.user.user_principal_name
+    tre_user_username        = var.admin_username == "" ? local.admin_username : var.admin_username
   }
   nexus_proxy_url = "https://nexus-${data.azurerm_public_ip.app_gateway_ip.fqdn}"
 
diff --git a/templates/workspace_services/guacamole/user_resources/guacamole-azure-windowsvm/terraform/variables.tf b/templates/workspace_services/guacamole/user_resources/guacamole-azure-windowsvm/terraform/variables.tf
index c6fb74d83..82c340359 100644
--- a/templates/workspace_services/guacamole/user_resources/guacamole-azure-windowsvm/terraform/variables.tf
+++ b/templates/workspace_services/guacamole/user_resources/guacamole-azure-windowsvm/terraform/variables.tf
@@ -37,14 +37,14 @@ variable "key_store_id" {
   type = string
 }
 variable "auth_tenant_id" {
-  type        = string
-  description = "Used to authenticate into the AAD Tenant to create the AAD App"
+  type = string
 }
 variable "auth_client_id" {
-  type        = string
-  description = "Used to authenticate into the AAD Tenant to create the AAD App"
+  type = string
 }
 variable "auth_client_secret" {
-  type        = string
-  description = "Used to authenticate into the AAD Tenant to create the AAD App"
+  type = string
+}
+variable "admin_username" {
+  type = string
 }