Bismark,
To flesh out your numbers:
2 aircraft AAR capable - at least 1 airborne, 1 ready on deck
Embarked 2 + 1 extended readiness + 1 spare/trg ac = 4 ac flt
Double flt the requirement for Harmony, UK training, roulement etc = 8
To provide 8 ac with minor recs etc = 11 aircraft Sqn
Virtual OCU commitment to augment US Navy trg or provide limited UK OCU = 2
Total fleet strength = 13 ac
For fleet / depth / fatigue / attrition management over 25 years=
11 (don't count 'virtual' ac) x 2.3 ac (pretty low multiple) = 25.3 aircraft
MoD will round down 25.3 to 24 'at risk' so just 24 aircraft and support required. Perhaps we could gamble this down to just 20 aircraft and trust to luck. Still a fair pile of money and the loss of 3 gusting 4 slots from the carrier plus a unique set of spares and engineering effort.
Or use the F35 in the buddy-buddy role, save the unique fleet, OCU, spares, support authority and have the worlds most expensive tanker flying circles.
It's not going to be cheap either way, so I guess we could park the carrier near a suitable diversion... or perhaps embark the aircraft at the 'div' in the first place.