Continuity mistake: Interior shots of Ivy's cafe show a window in the back wall of the kitchen, visible through the door to the dining area. Exterior shots of the building show only a plain stone wall where the window should be.
Continuity mistake: When Frank is on the phone taking down the details off his boiler repair job, he is told the address is 26 Upton Down, but the house where Frank does the job is number 24.
Continuity mistake: In several episodes of the show, Richard Beckinsale's hair changes length and style during individual episodes.
Suggested correction: Not a mistake. The show takes place over more than a year in the prison. People change their hairstyle and length during that time. Just because episodes are next to each other does not mean they happen within a very short period of time.
While the mistake is vague and should include a specific example or two, the mistake is saying that within an episode the hair changes, not that the hair changes between episodes.
Continuity mistake: Bob and Terry go away for the weekend in Bob's car, a blue four door Vauxhall Viva, registration number JCU 331G, but in the next episode "The Expert" they come home in a two door Vauxhall Viva, registration number ALF 132H.