George VIII's successor

[Bigal]

If the Abdication Crisis had not occurred, or indeed if he had been restored to the throne as the result of a 1940 British peace treaty with Germany, who was George VIII's heir apparent?

I can't find a record of any children, and while my guess is Elizabeth, George VI's daughter, I'm specifically looking for who it would be if George VI had renounced the claims of himself and his successors.

Any help would be greatly appreciated.