DB was a sqn ldr when shot down, so presumably repatriated as such. No promotion whilst in prison camp, yet a year or so after returning to UK he is a gp capt, when many are being reverted to substantive peacetime rank. So how com he skips through wg cdr to gp cap so quickly?
Secondly, and excuse my ignorance - what is actually the difference between machine gun and cannon, merely calibre, or a different way of loading and firing the two different weapons