Revealing mistake: A minute or so after the health and fitness instructer dies, we see her lying flat out on her back. If you look carefully, you can see her chest moving up and down and breathing despite being dead. (00:13:05)
Revealing mistake: When Victor and Margaret arrive back from her goddaughter's, they find their new wallpaper has been stripped. Margaret then goes up the stairs to bed and through the arch window you can see her stop at the top of the stairs waiting for the scene to end.
Deliberate mistake: In the shot where we see the cars in front of Victor's (shortly after Victor gets out of the car and gets back in when the traffic starts moving) you can see that after the white car on the right that there are no more cars even though the episode takes place in a traffic queue! If you listen to the commentary on the DVD, writer David Renwick points out the mistake and informs us that they had a limited number of cars for the shot. (00:11:25)
Continuity mistake: If you look at the corner cabinet in the Meldrew's kitchen near to the door that leads into the living room, you will notice that in some shots there is an ornamental chicken and in other shots it changes to a different blue coloured ornament.
Continuity mistake: At the beginning of the episode Margaret enters the living room and discovers that their new wallpaper has come down. In the shot from the kitchen, the wallpaper hanging down is not visible, but in the next shot there is a piece hanging down which should have been visible in the previous shot. (00:01:20)
Visible crew/equipment: On the train at the start, after everyone has left except Victor and Margret, you can see a boom operator reflected in the door's glass panel. You can see him and it's even more noticeable when he lowers the boom for when Victor sits down. (00:04:05)
Visible crew/equipment: When Margaret is about to confront Victor with the truth about his reflexology, in the first shot that pans over to Margaret on the very left of the screen, a hand appears and pulls the door back. It can't be Jean as we see her leaving the room to go upstairs a few shots earlier.