Strangers on the Shore - S9-E2
Deliberate mistake: When Del, Rodney and Boycie first arrive in France, there is a side view of the white van they are in and it is clear that the driver is definitely not David Jason.
The Hit Car - S1-E3
Deliberate mistake: While Bill and Ralph are with Starlet in the motel room and the shooting starts Bill tells Ralph to go get the guys, and when Ralph changes into his suit and flies out of the window, the shot inside the bathroom is a flipped shot. Not only is Ralph's watch on the wrong wrist in this shot, but later the bathroom is shown the correct way. (00:15:15)