Continuity mistake: The Gentlemen's and Ladies' Department is on the first, third, or fourth floor of Grace Brothers, depending on the episode.
Continuity mistake: In this episode, it is revealed that Mr. Lucas' first name is Dick; but way back in series 2 ("The Clock"), his first name is given as "James." This discrepancy takes place a few times over the course of the entire show run.
Continuity mistake: Mr. Lucas says the figures for the previous Monday were 325 pounds, and at that point in the day the departments combined (170 and 150) were up to 320, five pounds short. However, later when Mr. Rumbold is talking to Mr. Grace about the sudden drop in sales, he says they are "still 20 pounds short" of the previous Monday.
Continuity mistake: At the end of the show, after they reveal the 'new' ladies department. Mr Grainger is not wearing his glasses, as Mrs Slocombe has them in her purse, the shot changes to Mrs Slocombe, then back to Mr Grainger he is wearing his glasses, and there is no way he could have got them from Mrs Slocombe.
Continuity mistake: Mrs Slocombe is showing a bride a veil and puts it on the counter, but in the next shot she is still holding it and puts it down again.
Continuity mistake: The set up of the canteen changes from episode to episode. It is never the same way twice.
The Hold Up - S10-E3
Continuity mistake: When the robbers have nodded off and Mr. Spooner and Cpt. Peacock cut themselves out of the rope tying them to the cabinet, a clock outside is sounding the hour; if one listens it chimes nine times. But minutes later, after the rest of the group have come in and they make the call to Mr. Rumbold, the latter exclaims "It's after midnight." upon answering the phone even though less than ten minutes have passed.
Continuity mistake: Sometimes Mrs. Slocombe has discretion over both inventory and displays and what they will and will not sell in the ladies department, other times its Captain Peacock, Mr. Rumboldt or others that have the final say.
Continuity mistake: Normally the windows in Mr Rumbold's office are latch swing open style, but when the staff are viewing the parade they are plainer push up windows.
Continuity mistake: Mrs Slocombe arrives with her hair in disarray, but once she walks away she only has time to put her coat away before she returns, by that time her hair is neat with no evidence of it being messy. She had to have returned quickly to hear Mr Humphries' story as she comments on it shortly after.
Continuity mistake: In the ruined photo taken of Old Mr. Grace and his nurse and secretary, the secretary is looking away from the camera and her leg is raised. However, in the scene preceding, she was looking at the camera and raised her leg after the flash went off. Also in the photo, both of Mr. Humphries' feet are in the air, though one was on the floor when the picture was taken.
Continuity mistake: If a character says their assistant number throughout the show, they are different each time.
Answer: That wasn't possible in 1972. Until recently squatting was a civil offence in the UK, not a criminal one, and removing squatters was a complex and time consuming business.