Of course there is a strong desire within the RN to maintain FW capability; the 1st Sea Lord knows now this too and that without other countries letting our FAA Harrier pilots fly their toys for 8 years that its future is very uncertain. The arguments have mostly always been about maintaining carrier experience but the flying experience that 99% of the RN and RAF Harrier boys and girls have today is almost completely different to that required for conventional carrier ops. In fact, the most current conventional carrier pilots the UK has are likely equally split amongst the RAF and RN 'few' on US F-18 exchange tours. For FAA survival that proportion needs to swell in the RN's favour in order to back up 1SL's case in MoD; to be told that the RAF have just as many qualified wouldn't cut it, would it. So the RN have begun putting their pilots into any carrier flying job they can get - wise move too if you want to survive the many reviews and PR11 options that will come over then next few years.
The pilots will only need a rigorous work up some months prior to their first embarkation on HM PoW with F-35C; indeed that's how one usually approaches doing anything for the first time. Experience will be quick to come in so far as flying on/off is concerned which is probably why the RAF aren't making the same argument. Getting pilots flying off carriers now is not about keeping conventional carrier experience or even maintaining it, it's about the survival of the FAA FW tradition and nothing else.