Not entirely true, Not_a_boffin...
There was USS Lexington AVT-16... which had been the USN's training carrier since 29 December 1962, and which served in that role until her decommissioning on 8 November 1991.
So it is possible (however unlikely) that Ronnie Raygun was proposing loaning "Lady Lex" to the RN.
And yes, she was fully operational, since her training duties were to steam out from NAS Pensacola Florida into the Gulf of Mexico to make big circles in the water, and let the fledgling flyboys bounce birds off her deck (with the occasional "catch a wire and get thrown off the bow" joy-ride thrown in).
At that time, those birds were TA-4F Skyhawks and T-2 Buckeyes... both jet-powered small planes.
I'm sure Harriers & Gannets (if any AEW birds could be scrounged up) as well as Wessexs, Sea Kings, Chinooks, etc. would work fine off her deck, as it was nice and spacious. Of course, the Harriers would need to be real careful just where they set down, as most of her flight deck still had its wood covering.