Fallacies:
The island-nation needs sea power mantra is a fallacy. It is a fallacy in that we, with Europe, are part of a global trading system. The only bit of the island philosophy that is true now is the Channel/North Sea/Irish Sea bit. For the rest, we are with Europe and it is Europe that needs to prottect its SLOC and not UK alone. Nor is it simply littoral states that should provide sea power. Some littoral states punch well below their weight, if they punch at all. Naval power should be on a European basis.
Keeping our hand in for CV ops using exchange postings is also a fallacy. Exchange postings are just that. If we have no FAA then there wiill be no relevant exchange postings. By their nature exchange postings are supposedly cost neutral. As we could not exchange we would need secondment instead at an order of cost of perhaps 4 or 5 times salary or more (guessing here).
Back to point one; if we do naval air best then that is what we should strive for and allow or persuade our European partners to provide the screen. For exchange, parlo italiano?