Earlier economic revitalisation, and one of two options: either a more successful decolonisation, with less foreign pressure and more time to build up British backed 'moderate nationalists' in halfway decent countries, that manages to retain more small colonies across the world and a closer commonwealth, OR abandon the Empire rapidly and return to Europe.
Or a better fought WWII, with Germany being defeated in France, 1940, could leave Britain in a massively better postwar position.
Somewhere in the multiverse the Tories don't unseat post-war Labour until the end of the 50's/start of the 60's and the Socialist International is THE union of European nations; while the French have had their backs completely turned away from Europe focused on maintaining or even expanding their doomed colonial empire. NATO is never formed either and US influence in Europe consists of an army stationed in West Germany and West Berlin.