Continuity mistake: In "Down in the Jungle" (2-2) Beaumont says that both his parents have died, but in "Twenty-One Today" (4-8) he is reading a book that his mother has just sent him. Then in "The Last Roll Call" (8-7) Beaumont again says he doesn't have a mother.
Continuity mistake: The university that gunner Graham was educated at varies from Oxford to Cambridge. He's only got a single degree, so can't have gone to both.