Communication Problems (a.k.a. Theft) - S2-E1
Continuity mistake: During the opening scene where Polly is arguing with Mrs Richards over "giving change", the loose papers on the reception counter keep disappearing and re-appearing between shots.
Continuity mistake: In the episode "The Wedding Party", the first two rooms on the second floor right of the stairs were 11 and 12. Yet in this episode, those two exact same rooms are now 5 and 6. (00:19:20)
Continuity mistake: In this episode, Basil hides in a closet to try and trap a girl staying the night in a guest's room. However, in other episodes ("Wedding Guests," "Communication Problems," and "The Kipper and the Corpse"), there is a room in the same spot the closet is in this episode.
Continuity mistake: After the woman screams, Sybil knocks the wall and you can see it move.
Continuity mistake: When Basil is talking to Mr. Hamilton in the dining room there is smoke coming from the kitchen. The next moment he goes into the kitchen and all the smoke is gone. (00:24:00 - 00:25:00)
Continuity mistake: When Basil brings the Hamilton's their bottle of wine, he fills up Mr Hamilton's glass but not Mrs Hamilton's. However, a couple of shots later, we see both Mr and Mrs Hamilton drinking wine from their glasses despite nobody pouring any wine into Mrs Hamilton's glass.
The Kipper and the Corpse (a.k.a. Death) - S2-E4
Continuity mistake: When Basil, Polly and Manuel are trying to hide the body in the cupboard in the guests' bedroom, the door behind them leading to the bathroom mysteriously opens and closes between shots throughout the scene.
The Kipper and the Corpse (a.k.a. Death) - S2-E4
Continuity mistake: When the guest from number 8 is going up, in one shot Basil is looking on his watch when you see him from behind but not from the front a split second later.
Continuity mistake: Near the beginning, when Sybil goes into the office after speaking to Basil about the date, the lights are obviously on in the office, but when she walks out, it can just be seen on the right that the office is in complete darkness, and then when the shot changes back to the regular one in the lobby, the office is lit up again, without anyone going in there in the meantime.
Basil the Rat (a.k.a. Rats) - S2-E6
Continuity mistake: When Basil and Sybil are talking to the public health inspector in the kitchen (on his second visit), Basil breaks two bottles of wine. When he removes the second bottle, there are two bottles remaining on the rack, but when the camera cuts away and then back when he breaks it, there is only one bottle left on the rack.
Answer: It's "Leisure Complex" by Dave Gold and Gordon Rees. Can be found on YouTube. The relevant clip is around 25 seconds in.