It has been known for the show to have some in-jokes with its credits, occasionally substituting a credit shot with an alternate one.

The first instance of this occured with Fisher and Celia’s shot that debuted in Set 3 of 1988’s credits, where normally she would walk in from the right hand side, peer over his shoulder to try and read his mail, and get caught doing so.

In the alternate shot, Celia would not appear. Fisher then looked over his shoulder to see where she was, at which point she would sneak in from the left hand side of the screen and finally get to read his letter.

This shot aired for the first time in Episode 111 (Monday 20th June 1988), with subsequent appearances in Episodes 119, 131, 155, 186 and 201.