F-18G should have been purchased for the FAA and then palmed off to the the RAF after 15 years once F-35 is mature or F/A-XX is available.
Hand over the F-18s to the RAF when they get replaced, reduces cost, reduces risk and gives a proven combat capability now as well as some post GR4 a/c for the RAF.
Also keeps the carrier future proof by proving AAR/AWACS compatibility for when we can afford it, and a platform for future UCAVs which I'm sure will be catapult launched.
What's so difficult about that MoD Muppets FFS !!!