Nothing in Boulting’s credits on IMDb seems to fit, although he did make “Journey Together” about a bomber navigator, which came out in 1945.
Wikipedia has an A-Z of British WW2 propaganda films too:
https://en.wikipedia.org/wiki/Catego...opaganda_films
If it was a short rather than a feature film, I’m not sure where you’d look. You could search Ministry of Information which I think was in overall charge of films