May I offer a Foundation 101 before offering thoughts on: “never happened” and “not with UK”? The de-colonisation of E/SE Asia has been captured by revisionists, so I/we can't talk about its effect on UK aircraft programmes unless we have a consensus on context. I start from this perspective and would welcome input before I turn that into my take on the Q:
What Actually Happened:
9/45: Stalin angered by exclusion from Occupation of Italy and Japan, both having killed many Ivans. So he turns to open material support to Mao and to plausible denial in stirring Assymetric Warfare to ensure friendly replacements in ex-Japanese Occupied territory.
By late 1949: USSR has reduced its presence in Korea to a Naval base, US in the South to a training cadre. Nobody helped Neths. to stay in (more of) E.Indies; US helped Philippines to deal with Mao's Freedom Fighters. ANZ is helping UK deal with more in Malaya; US helps France 7/49 with P-63C Kingcobras to deal with more in Cochin China. By 6/50 Mao has tidied up Hainan and Tibet, leaving only Formosa, HK and Spratlies until he might have a Navy.
Kim the First sees a chance to push S.Rhee into the sea and asks Mao+Stalin for money & material, but not men. They agree and Kim invades, 25/6/50.
US Aid Programmes to 6/54 cascade vast money and kit to Allies. Most here know of end-items (RAF B-29/Neptune/Sabre, RN Avenger/Skyraider): we do not all know of part-funding of UK R&D and production (NATO Standard Types included Swift, Hunter, Venom) and some of us do not know of US supply, free, of factory plant and equipment - much of A300B's British and French structure was made off US machine tools put into Hawarden for Vampire, Filton for Venom, Toulouse for Aquilon (yes, really!)
What If: Case A: MacArthur stops at 38th. Parallel, 10/50 and does not push towards the Yalu.
Case B: No UN Resolution (because Molotov was in NY, 25/6/50, to veto), so:
UK takes the same position as it was taking on France-in-Vietnam: to ignore.
But US goes gung-ho (as JFK/LBJ would in 1964), quickly finding who are its friends.