Other mistake: When the man at the start is thrown through the room and his head hits the wall, the picture briefly freezes.
Other mistake: The sign which Silver reads says that one's got ten seconds to get away after pulling the chain. But in fact, after the monkey pulls the chain, fifteen seconds pass before the detonation (I've been counting).
Other mistake: The interiors of Miss Price's house is definitely not from a British country house. The ground floor looks more like an American 70's house.