Service personal were not demobbed for ages after the official ending of the war. Just checked dates the first official demob was 6 week after VE Day (18th June 1945) Personnel were still being processes a year later. Apparently 4.3 million were demobbed. But you still have conscription from 1946 to 1963.
You also have to add 48.000 Bevin Boys and 80.000 (Women's Land Army) and Lumber Jills. Never realised they were conscripted from 42 onwards.
Also 950.000 women worked in the munitions factories.