Sounds like "2+2=5" to me. It is only natural that Cdr JHC would like to get on the record his aspiration that his forces should have the best equipment - that way if an incident happens and the response is criticised he can say "I asked but wasn't given the money". It also makes complete sense for UKSF to conduct famil flying with the Mildenhall based CV-22 community, which, doubtless, in time of acute national need would be made available.
Any UK purchase of V-22 is probably quite some way off. As ORAC suggests, the RN COD requirement may well be the "foot in the door" that would permit a small number of V-22s to be purchased for JSFAW - probably to enable 7 Sqn to release the Mk6 Chinooks back to SH and to have a blend of "fat tank" Mk5 Chinook and V-22. We'd need at least 6 frames to provide 2x FL, 1x Trg/Spare and 3 in either light or deep rectification. Double that to include COD and the number is probably between 12-16 airframes. There are already RN pilots flying the V-22 on exchange so "crews training in the US" is true as well.