diff --git a/docs/c4-diagrams-as-code/trs-c4.dsl b/docs/c4-diagrams-as-code/trs-c4.dsl
index 5d3d052a6..9379b8054 100644
--- a/docs/c4-diagrams-as-code/trs-c4.dsl
+++ b/docs/c4-diagrams-as-code/trs-c4.dsl
@@ -6,6 +6,7 @@ workspace {
 
     support-user = person "Support User"
     citizen = person "User (Citizen)"
+    emp-prov-la = person "Employer, Provider, LA"
 
     softwareSystem = softwareSystem "Teaching Record System Core Containers"{
 
@@ -34,23 +35,32 @@ workspace {
         active-directory = container "DfE Active Directory" {
           tags "Corporate Sysytems" "AD"
         }
+        dfe-sign = container "DfE Sign In" {
+          tags "Corporate Sysytems" "DSI"
+        }
       }
 
-      aytq = group "A Teacher Service e.g.Access Your Teaching Qualifications" {
+      aytq = group "Access Your Teaching Qualifications & Check A Teachers Record" {
 
                 aytq-web-app = container "AYTQ Web App" {
                     tags "Access Your Teaching Qualifications" "AYTQ Web App"
                 }
 
-                container "AYTQ Database" {
+                aytq-ctl-db = container "AYTQ & CTL Database" {
                     tags "Access Your Teaching Qualifications" "Database"
                     aytq-web-app -> this "Reads from and writes to"
                 }
 
+                check-web-app = container "CTR Web App" {
+                    tags "Check a Teachers Record" "CTR Web App"
+                }
             }
 
+
+
       support-user -> trs-web-app "Uses Support Application"
       citizen -> aytq-web-app "Visits Service"
+      emp-prov-la -> check-web-app "Visits Service"
 
       trs-web-app -> active-directory "Uses AD API to Authenticate User"
 
@@ -64,7 +74,10 @@ workspace {
       trs-auth-server -> aytq-web-app "OAuth"
       aytq-web-app -> trsApi "Uses"
 
-
+      check-web-app -> aytq-ctl-db "Reads from and writes to"
+      check-web-app -> trsApi "Uses"
+      check-web-app -> dfe-sign "Uses DfE Sign to authenticate user"
+      dfe-sign -> check-web-app "Return OAUTH claim"
 
     }
 
diff --git a/docs/c4-diagrams-as-code/trs-core-containers.jpg b/docs/c4-diagrams-as-code/trs-core-containers.jpg
index e291ea599..b8b99d728 100644
Binary files a/docs/c4-diagrams-as-code/trs-core-containers.jpg and b/docs/c4-diagrams-as-code/trs-core-containers.jpg differ