65 000 tons of steel is worth quite lot. You don't have to sell them to someone who will use them as carriers! (I don't advocate this COA)
Orca - I don't understand your GR4 point. JSF is, at least in part, going to replace GR4 so yes, it is a maritime strike capability, but it is also going to be a land based capability hence the main reason why the entire thing is joint RAF/RN. As a hard up UK plc we will need to be flexible with where we operate from, we don't have the luxury that the USA has of a dedicated carrier force and a dedicated land based force. If the next 20 years are like the last 20 then JSF could spend the vast majority of its time flying from land on operations not fom a carrier. If we spend the next 20 years trying to recapture the Falklands then the basing will be a carrier.
Last, I do find it amusing that some spun the change to F35C as an RAF plot to somehow do over the RN and now the change to F35B is being spun (by a few) as another RAF plot! More tinfoil hats needed, me thinks.