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.
Answer: It's "Leisure Complex" by Dave Gold and Gordon Rees. Can be found on YouTube. The relevant clip is around 25 seconds in.