Continuity mistake: Watch the Butler standing in the background after the committee exits the meeting room. A very bad edit causes him to jump to a different position (a foot further away than he was before) between shots.
Continuity mistake: An estate car can be seen crossing the background in one scene, as opposed to the village "taxis."
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