The BBC's film library was all like that - full of stuff showing typical British pluck, indomitable spirit and stiff upper lipness and a distinct absence of bad language even under the most adverse of situation.
FB mentions this because 21 February is the birthday of Douglas Bader, who was born in 1910 and died in 1982. Reach for the Sky may be accurate in many ways, it may be fictional in others (in particular the amiable and polite Kenneth More was nothing like the headstrong Bader in real life who used bad language with the enthusiasm of a contemporary comedian). What the film does not show is Bader's cricket career.
Bader also played cricket in a German prisoner of war camp - despite his disability. He had been shot down over France in 1941. It is not known whether such close up experience of cricket had a significant impact on German morale. FB would like to think cricket's contribution to the defeat of Nazism was important. Bader certainly would have supported this - as a prisoner he was determined to make life difficult for his captors and was a serial escapee to the extent that the camp officers threatened to take his legs away. Instead he was confined to the escape-proof Colditz - where there was no cricket pitch. No wonder he wanted to escape.