The removal of the pressure for CVA 01 to be designed in the early 60s and the availability of 1 or 2 Audacious class in service with F4/Buccaneer pushes the carrier replacement question into the 70s or later.
Assuming the Centaurs are available as LPH/CVS their replacements get designed first. A gas turbine powered Centaur style (rather than Invincible/Command Cruiser/Escort Cruiser) is ordered in the early 70s. If the troubles of the 70s delay them, the lead ship is not available until 1979. They might not survive the defence cuts in 74 to 77 though NATO would have lobbied hard to keep them. The first replaces Bulwark . Albion or Centaur are likely victims of the withdrawal from EoS and Malta. Hermes stays as her early 70s mod.
The RAF gets P1127RAF but it is unloved and unless the US Marine order comes along, the small RAF force dies with the arrival of Tornado or equivalent.
The surviving Audacious (either Eagle or the namesake) needs replacing in about 1983/4.
Ark as spares hulk is replaced by the other ship.
The decision has to be taken in the mid to late 70s
Frankly, given the poor condition of the UK in this period, I think the carrier force would be onborrowed time. NATO would press to keep theexisting force.
When (or if) the Thatcher government arrives in 1979 matters get worse. Trident was MT's pet defence project. As in 1962 other RN work gets sacrificed for the nuclear deterrent.
The only design of this period is the US conventional alternate to the Nimitz.
[URL unfurl="true"]https://en.m.wikipedia.org/wiki/Aircraft_Carrier_(Medium)[/URL]
Such a ship would be able to operate F18 in due course.
