First i'll say that
@Ato's is probably the most comprehensive treatment of the issue so far, and to it I'd add the point that, along with keeping corporate budgets tight during the Age of Austerity, the other thing that delayed excellent British (civil especially) aircraft programs was a curse for British industry generally from the 1920s-30s on to the present. That was: you've got a limited pool of money, and there is an
absolute demand that those old-school-tie shareholders over in the City get a substantial cut or they'll take their business elsewhere (this helped kill British textiles, long-term, back in the Slump when the "gentlemanly capitalists" as an old prof of mine, Anthony Hopkins -- the ex-Cambridge professor of British imperial history, not the Welsh-American actor -- termed them strongarmed their fellow public-school old boys in the National Government into not raising tariffs on Indian textiles bc said gentlemen had big investments in India that needed to be paid off by Indian mills turning out fabric at substantially lower rates than the UK ones, who were both paying their remaining workers relatively decently and had just spent large sums more or less inventing modern synthetic fabrics.) As a result R&D and product testing budgets were repeatedly raided to pay off investors, pushing projects to the right. But British governments of both left and right had very little understanding of, or patience with, that situation. The effort to prop up an ex-imperial class of globalized investors with things like an overvalued pound and the Sterling Area helped bleed out the potential pool of funds to invest in Britain's once-legitimately powerful high-tech sectors French-style.
It speaks to a fundamental difference in the long-term conceptions of the French and British states (one shared at that time by the US state, with the federal government effectively a "warfare state" built up by the Civil and World Wars plus the New Deal programs, though much of that has been abandoned in unsteady increments since about the Seventies.) France always valued a centralized state -- the Revolution reinforced that rather than reversing it -- and viewed both its political stability and its geopolitical power in nation-state terms, so it was more willing to use nationalist, protectionist, and nationally instrumentalist tools and methods to maintain a France with
gloire (since, in De Gaulle's famous phrase, France without
gloire was nothing.)
Britain still worked with the Magna Carta model, a mighty and often informal "parliament" of upper-class rentiers who controlled the economic and cultural levers of power, spread via the "independent" schools (let's just say public shall we? That's been one of the great Orwellian trends in "imaging," finding a new word to obscure what "public schools" means in British English) and a handful of ancient, select grammars, the senior universities, and on out into the Square Mile, the smoothest paths of entry towards standing for Parliament, corporate governing boards both private and quango, select senior professions like the law, and various cultural gate-keeper roles. They were unified in their Britishness (1) against the rise of any dominant continental power, whether French, German, or Russian, and (2) most unified in their role in Britain's political economy as a class of
rentier investors. They never particularly
liked the high costs of doing business at home, nor did they like how much you needed to pay out in order to maintain bleeding-edge industrial technology sectors, or the formal apparatus of state like large overseas garrisons, public welfare provisions, or protectionist policies to help domestic industries thrive. So far as they were concerned the Industrial Revolution was an accident in the backyard that made too many rough tradesmen into millionaires, and should be outsourced as soon as possible, which they promptly got on with throughout the 20th century. In the process what might have been the South Korea of Europe (outsized importance in high-tech industries and outsized military power) became the sick man of the West because
being the South Korea of Europe was not where the easy money was for maintaining cultural and political dominance.
Probably not to cancel the Malta class. The UK made some really stupid decisions when it came to their carriers post war. It seems like they made the exact wrong decision each and every time. It really was a tragedy of errors. So complete the Malta class, cancel the Centaurs instead. Then retire the Audacious class once the Maltas are in service
This. Kill the
Illustrious-class dead as worn out by active service
and at the same time kill the
Audacious-class ships prior to production as half a loaf. Build two
Maltas and three rather than four
Centaurs, in the process cancelling the proposed second
Centaur batch just as IOTL. Recognize that those ships perform several useful purposes: (1) effective sea control in late-imperial shipping lanes important to the Sterling Area (that's how you sell it in Cabinet) and that support a retreat to informal Commonwealth-based empire rather than the costs of formal control, (2) effective surface-fleet command and sea control facilities so that the UK can remain a legitimate supporting partner of the US rather than just one of several worn-down Western European states with a slew of frigates, (3) that a combination of wide-ranging aircraft with more and more airborne ASW capabilities, allied to a larger force of submarines, is probably the most effective way to counter the Northern Red Banner Fleet's wolf packs (call it an "above-below" approach, smaller but more powerful surface groups centered on flat-tops with lots of aircraft to swat down anti-shipping bombers and drop sonobuoys and torpedos, plus beefed-up production runs of subs bc often the best way to kill a submarine is with
another submarine.)
Maltas get the big-war fleet command role,
Centaurs center their work on the East-of-Suez areas. Then in the Sixties you ditch a
Centaur, don't modernize the decks of the other two, and convert them to commando carriers. With the US getting involved
somewhere (as I like to say, Butterflies and Trends, and the Trend was that by the Sixties the US were going to find someplace to sink costs in the anticommunist struggle) they will appreciate having an RN strong enough to spell them up in the North Atlantic -- frankly the USN has always valued the Royal Navy more than Her Majesty's Government or even the MoD post-1945 has. That lets your fleet generate a
Malta task group for the North Atlantic (and possibly one or two small hunter task groups centered on whatever sort of
Tiger-class cruisers emerge ITTL), and a
Centaur commando carrier group for expeditionary issues (Norway, Cyprus, emergencies in the BOTs, etc.) Smaller surface escort fleet centered on those groups rather than on spreading the post-imperial butter too thin with a second- or third-rate frigate in every port, more subs especially SSNs in service,
Island- or later
Castle-class style ships in the BOTs and Hong Kong just armed up a bit (e.g. the moment Bofors builds a decent 57mm get a license for them and drill them into the decks of
Castle-equivalents. This does not make them "warships," it means they can properly overmatch their security duties and if someone starts a war with you, can go down shooting which looks better in the papers if they're going to get sunk anyway.)
That probably lets beaten-down carriers (fleet and commando) slump into the Eighties, by which point they have been relevant
somewhere on occasion (Suez, Malaysia/Indonesia escalates, chastising UDI, Belize, Cyprus, Falklands, take your pick.) At that point if there is any capacity, build a unitary class of three in, at the very least, CVA-01 range of dimensions (the early designs, not the fatally compromised later ones) with the intent to run a fleet carrier, a commando carrier, and a backup for either role in refit. At that point costs of technology as much as any fluctuations in the Cold War will drive down escort numbers, the key thing is to maximize what you've got. So invest in OTL-Type-23 style quieting and towed sonar, in phased-array radar when it's available, in vertical launch ASAP, in sea-launched cruise missiles, etc. Accept that cost spirals mean you
have to trade quantity for quality if you plan to stay relevant and get out in front rather than dither while trying to have both and fall behind. That would preserve a basic strike carrier capability, allied to a real effort to get all of 3 Cdo Bde RM on shipboard and land it in a combat zone, right down to the present.