Below a link to the Royal Oak Club website where you can find all the references of Royal Oak.
http://www.royaloakclub.com/search/?search=search_reference&ref1=&ref2=25770&ref3=&ref4=&ref5=&ref6=&ref7=
I think MichaelC will give you soon a better (and definitive) answer than I to your question.
Best wishes
Alkiro