The British, depending on how decolonisation in Africa goes, might end up going for what was suggested in OTL and replacing the British Indian Army with a British African Army, which might push the problem into the 1960's/1970's.There's a very simple answer to that - rapid mobility. In OTL, this was one of the driving forces behind Sandystorm - the UK couldn't afford the big conventional forces needed by the existing strategy. To his eternal credit, Mountbatten realised this - he offered Marines and Carriers for East of Suez duties, a "cheaper" alternative to the V-force, and to scrap the rest. The other two services went in trying to do business as usual, and got cut off at the knees.
ITTL, things are slightly different - they've got a lot more money, but the manpower constraints are if anything tighter (bigger economy and full employment hitting earlier) and they've got an even more widespread set of commitments. I think that means an earlier move to air mobility instead of sea mobility, and the V.1000 was also intended to do double-duty as a tanker for the V-force which would be a critical requirement ITTL since the Soviets aren't the only peer threat. So I think we'll end up with something like this in significant numbers, a relatively small professional army and lots of nuclear weapons to make up for the size of the army if they ever have to fight a peer competitor.
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