Continuity mistake: At the end, Number 6 and the Butler catch a bus near Westminster Bridge in London. The bus that drives up and stops for them has no back platform. But when they board, the style of bus suddenly changes to the more common type with an entrance in the back.
Continuity mistake: In the final scenes, as helicopters are taking off from the Village, the bell tower that's always been there is visible in some shots, but in others, it has disappeared.
Continuity mistake: The council members' signs keep changing during the "Dem Bones" sequence. "Entertainment" becomes "Anarchists" and several others switch places between cuts.
Continuity mistake: In the opening scenes, Number 6 steps onto the elevator with a beard, but arrives on the lower level clean-shaven.
Chosen answer: We're led to believe Rover is some kind of robot in the series. According to books on the show, Patrick McGoohan was looking for an unusual guardian for the Village, looked up at the sky, and saw a weather balloon, which was what Rover was.
Captain Defenestrator