CBFlood,
“SND R Keene”'s solution is fine but requires you to specify an actor, to remove this requirement:
// in the "meta" declaration add:
"WorldContext = "WorldContextObject"
// then in the method declaration pass the object
class UObject* WorldContextObject
This way you can get the level name without requiring an actor, like:
GEngine->GetWorldFromContextObject(WorldContextObject)->GetMapName();
That’s it!