How to Destroy NetworkLobbyManager

I’ve been having some issues with NetworkLobbyManager. To work round, I decided to try to Destroy and recreate the NetworkLobbyManager each time the player comes back to the main screen.

I use the code below:

private void ResurrectNetworkManager() {

    if (lobbyManager != null) {
        Debug.Log("killing"+lobbyManager.gameObject);
        DestroyObject(lobbyManager);
        Debug.Log("creating again");
        lobbyManager = Instantiate(lobbyManagerPrefab);
    }
}

It seems to Destroy fine. But when the instantiate happens again, I get the following:

Multiple NetworkManagers detected in
the scene. Only one NetworkManager can
exist at a time. The duplicate
NetworkManager will not be used.
UnityEngine.Object:Instantiate(GameObject)
MainMenuManager:ResurrectNetworkManager()
(at Assets/MainMenuManager.cs:35)
MainMenuManager:Awake() (at
Assets/MainMenuManager.cs:24)

Is there some trick I need to do to fully destroy the NetworkManager?

The Destroy should actually work for this - seanr kindly raised it as bug 712042.