Other mistake: Whenever you see the gates to the yard during the show they are painted green and have a "Wright and Boston scrap metal merchants" sign written on them. But right at the front of the opening titles of every episode, the gates are plain green with no sign-writing on them.
Here Come the Double Deckers (1970)
1 other mistake in Season 1 generally - chronological order
Starring: Peter Firth, Brinsley Forde, Gillian Bailey, Michael Audreson
Continuity mistake: When the gang first arrive at the stately home Albert parks his car next to a coach. When the camera angle changes the car has moved back a few yards, and when the gang leave the car has changed position completely.