When Darling gives his "bugger" line toward the end, he's still wearing an overcoat. After a two-second cut to Blackadder's response, we see Darling again, now without the overcoat.
Baldrick mentions Neville the Hamster as one of his friends. Asian hamsters were not bred in captivity until 1930, and only after then did they start to become domestic pets in Europe and North America.