I found @Riain's proposal to build 2 CVA.01s (with 6 Olympus gas turbines driving 3 shafts) instead of the 3 Invincibles appealing.So, I wonder about the following whatif...
Whatif "escort cruiser with Harriers on deck" circa 1964-68 become a poor's man "Plan B" to
a) P.1154 on CVA-01 (the horror, the horror)
b) Phantoms on CVA-01 / Eagle & Ark Royal / the last Centaurs (none of these tree carriers being a satisfying answer)
Fundamentally, Harriers-on-Invincibles replaced Phantoms-on-large-carriers because "NATO ASW" become far more important than "East of Suez"
So in a sense, not only CVA-01 doomed the British carrier fleet, but East of suez" agony and death was perhaps a larger nail in the coffin. The economy was the death knell, too.
Whatever the main cause, Phantoms on large carriers were doomed: future belongued to "Harriers on small ships".
Well, instead of waiting for Invincibles-and-SHARs after 1975;
"P.1127 / Harrier Mk.1 on Escort cruiser" right from 1966 ?"
The pros and cons are discussed here...
“All modern aircraft have four dimensions: span, length, height and politics………..” – Sir Sydney Camm. Objectives - Prevention of Global War Winning the Cold War Maintenance of Britain's ability to fight limited war Chief of Staff guidelines for military policy 1956 UK war plans of the...
I'm a believer in the steel is cheap & air is free theory (which says that hulls & machinery are a small portion of the total cost of a warships and weapons & electronics are the major portion) so I don't believe that it would have been prohibitively expensive to build.
Finding the larger crews would be the problem. However, changing to gas turbines would reduce the manning requirements and so would reducing the size of the air groups to the same size as Ark Royal in the 1970s. It could be brought up to full strength in an emergency by breaking up the training squadron, which is how they brought Hermes and Invincible's Sea Harrier squadrons up to full strength for the Falklands. Those measures don't fill all the gap, but they do reduce its size.