So... it worked out alright then?
Erm... to answer your Q's about the Ark Royal, I don't have the answers. I had always hoped for an encounter with a historical cap ship but finally resigned myself to simply trawling for targets when I played stock. If you go to Scapa Flow playing GWX3, though, there is a Revenge class parked in the bay... but it's on the wrong side of the bay to be the Royal Oak (plus, it's part of the scripted campaign layer; e.g. pretty much always there).