^^^ No expert on post-WW2 RN, but in this universe, wouldn't one of the known missions be general power-projection, especially where de-colonization either has hot spots, or palpable threats of the situation going hot. In those situations, Naval air power and the ability to land an expeditionary force in short order would be a useful tool for His Majesty's Government. From our history, Malaya, India, Suez, Kenya, Greece, Palestine, Cyprus, and others went hot (in some form) at one time or another. Here, the background conditions have changed considerably, so probably not the same list.
BTW, how will the French deal with their Empire, especially Indochina, post-WW2?
Note to self: be patient.... All will be revealed in its appropriate time.