Funny. I've just been reading a book on DB and his dislike of cannons. When his squadron were re-equiped with Spits they all got the Mk
Vb, with cannons. DB got a strop on so they gave him a Va - just machine guns. He had a few arguments with 'Crow' (Crowling-Milling) but it seems that his objection to cannons was one of the few times he was wrong.