It's already been developed so saves on the costs, and an enlarged version makes it into a proper strike carrier which the 'Clem's weren't as their air wing was limited by their cat's and lifts. An F-4 and Bucc' based air wing beats the F-8 and Etendard one.
Do the RN actually want to go with their CVA-01 project?
The CVA01 design was exactly what the RN wanted/needed, every design feature was arrived at logically.
For example the 54,000t version was chosen because the 58,000t version required a 4th shaft and machinery for no tactical value. The Sea Dart was included because the RN needed 8 Sea Dart ships in the Task Group, and USN carriers at the time carried the Terrier SAM. The Alaskan Highway outside the Island was an extension of the Alaskan Taxiway for support vehicles on the Eagle and Ark Royal that was found to work so well. That doesn't mean that carrier design is easy, it isn't and Britain had some particular limitations that made designing their particular requirement tough, the most well known one is the size; to fit into British docks the carrier could be no longer than about 960' and greater than about 58,000t which is why the Malta, the 1953 carrier, CVA01 and the current Queen Elizabeth are all about the same size - as big as Britain can handle.
CVA01 was cancelled because the incoming Labour government wanted to avoid devaluing the Pound, so chose an RAF East of Suez strategy that was cheaper (and less capable/flexible and based on incorrect assumptions about the P1154-RAF) than the RN strategy. After choosing the RAF strategy and announcing that Britain would withdraw EoS by 1975 they cancelled CVA01, not because the design was unsuitable.
