Or even something closer in time, the RN is able to deploy the BPF in 1941/2 instead of 44/5.
Possibly with US aircraft or even without, i.e. Seafires, Fireflies, Baracudas, possibly Sea Hurricanes further evolved into fighter bombers or even dive bombers, Sea Typhoons, Tempests, Furies, Mosquitos and Hornets. Implacables, Colossus CVLs, Minotaur (Swiftsure) class cruisers, Battle class destroyers, A class fleet submarines, maybe even Vanguard in addition to all fives KGVs, all pre-deployed to Sydney and forward based at Singapore.
RAF / RAAF / RNZAF operating Griffon Spitfires, Tempests, Furies, Mosquitos, Hornets, Lancasters, Halifaxes, Seafords. Land forces could be updated too, Comets, Centurions, Sextants, Avengers, (Cromwell Kangaroos?) but with a late war / post war BPF and RAF countering Japan chances are they wouldn't have much to do.