Creating a custom NetworkManagerHUD

I started out by debugging the stock JS example of the network connection script then tried adding some more functions. I believe what I am failing to achieve is setting the "Client Ready" state of the players. I would like this to be set automatically when possible, if possible. It appears to be capable of creating and joining a server using multiple clients based upon the console logs, although no players get spawned in. Console when creating a server:

 MatchMakingClient Create :https://eu1-mm.unet.unity3d.com/json/reply/CreateMatchRequest
 UnityEngine.Networking.Match.NetworkMatch:CreateMatch(CreateMatchRequest, ResponseDelegate`1)
 SimpleMatchMaker___:CreateInternetMatch(String) (at Assets/Scripts/SimpleMatchMaker___.js:15)
 UnityEngine.EventSystems.EventSystem:Update()
     
 JSON Response: [[UnityEngine.Networking.Match.CreateMatchResponse]-success:True-extendedInfo:]-address:52.28.9.224,port:9999,networkId:0x0640000000020E42,nodeId:0x037F,usingRelay:True
 UnityEngine.Networking.Match.<ProcessMatchResponse>c__Iterator0`1:MoveNext()

Similarly recognisable result when joining the server too.

OnMatchCreate, OnServerReady and OnServerAddPlayer do not generate Debug.Logs and therefore I'm fairly sure they're not being called.

From reading the documentation I understand if the server is running at least one of those is supposed to be called? Can somebody talk me through making this work?

Code:

 #pragma strict
 public class SimpleMatchMaker___ extends NetworkBehaviour {
     var playerPrefab1 : GameObject;
 
     function Start() {
         NetworkManager.singleton.StartMatchMaker();
     }
     //call this method to request a match to be created on the server
     public function CreateInternetMatch(matchName: String) {
         var create: UnityEngine.Networking.Match.CreateMatchRequest = new UnityEngine.Networking.Match.CreateMatchRequest();
         create.name = matchName;
         create.size = 4;
         create.advertise = true;
         create.password = "";
         NetworkManager.singleton.matchMaker.CreateMatch(create, OnInternetMatchCreate);
     }
     //this method is called when your request for creating a match is returned
     private function OnInternetMatchCreate(matchResponse: UnityEngine.Networking.Match.CreateMatchResponse) {
         if (matchResponse != null && matchResponse.success) {
             //Debug.Log("Create match succeeded");
             var hostInfo: UnityEngine.Networking.Match.MatchInfo = new UnityEngine.Networking.Match.MatchInfo(matchResponse);
             NetworkServer.Listen(hostInfo, 9000);
             NetworkManager.singleton.StartHost(hostInfo);
             
         }
         else {
             Debug.LogError("Create match failed");
         }
     }
     //call this method to find a match through the matchmaker
     public function FindInternetMatch(matchName: String) {
         NetworkManager.singleton.matchMaker.ListMatches(0, 20, matchName, OnInternetMatchList);
     }
     //this method is called when a list of matches is returned
     private function OnInternetMatchList(matchListResponse: UnityEngine.Networking.Match.ListMatchResponse) {
         if (matchListResponse.success) {
             if (matchListResponse.matches.Count != 0) {
                 //join the last server (just in case there are two...)
                 NetworkManager.singleton.matchMaker.JoinMatch(matchListResponse.matches[matchListResponse.matches.Count - 1].networkId, "", OnJoinInternetMatch);
             }
             else {
                 Debug.Log("No matches in requested room!");
             }
         }
         else {
             Debug.LogError("Couldn't connect to match maker");
         }
     }
     //this method is called when your request to join a match is returned
     private function OnJoinInternetMatch(matchJoin: UnityEngine.Networking.Match.JoinMatchResponse) {
         if (matchJoin.success) {
             //Debug.Log("Able to join a match");
             var hostInfo: UnityEngine.Networking.Match.MatchInfo = new UnityEngine.Networking.Match.MatchInfo(matchJoin);
             NetworkManager.singleton.StartClient(hostInfo);
         }
         else {
             Debug.LogError("Join match failed");
         }
     }
     
 //    public virtual function OnMatchCreate(conn: NetworkConnection){
 //        Debug.Log("OnMatchCreate");
 //        NetworkServer.SetClientReady(conn);        
 //    }
     
     public virtual function OnServerReady(conn: NetworkConnection){
         Debug.Log("OnServerReady");
         NetworkServer.SetClientReady(conn);
     }
     
     public function OnServerAddPlayer(conn: NetworkConnection, playerControllerId: short) {
         Debug.Log("OnServerAddPlayer");    
         var playerPrefab = GameObject.Instantiate(playerPrefab1, Vector3.zero, Quaternion.identity);
         NetworkServer.AddPlayerForConnection(conn, playerPrefab, playerControllerId); 
     }
     
 }