Change GameMode when async loading a new level

I am trying to get the game to load a level with a very lightweight gamemode to make sure initial loading times on PS4 are short.

I get my intro level with an animated logo and then call prepare map change. When map is ready I commit the map change.

This doesn’t change the Gamemode, so the game doesn’t continue from that point onwards. The only way to get the Gamemode to change seems to be to use OpenLevel. This is a blocking call and is not going to be good enough.

I have also tried level streaming in blueprints to the same effect.

Is there a way to get the gamemode to change when loading levels asynchronously?

Thanks