Largely speaking, they weren’t in a place to do so. Of course they tried to impose puppets (particularly in Africa) but the historical tide was simply against them. The y*ps, c**lies and n*ggers weren’t having any of it, and neither were the young radicalized cr*ckers at home. The British Establishment was powerless.
(Not to say they didn’t “put up a fight”, in one case – Kenya – they sent thousands to what were essentially gulags.)
No amount of soft or hard power was going to convince any of the above to embrace a new form of colonialism. And so we saw the British hastily carve up boundaries in their former possessions (India/Pakistan, Cyprus, Palestine, etc.) and get out of dodge.
I should add this didn’t stop them from intervening after they had left these places. The British had a strong hand in the removal of Iran’s democratically elected government, and in the assassination of, the Congolese revolutionary. (Also, need I mention Eire?)