Visible crew/equipment: Basil runs out of the kitchen and stops Doctor Abbott and starts talking to him. The shadow of a boom mic appears on the wall to the right of the screen twice as he talks to him. (00:15:25)

Visible crew/equipment: When Basil's trying to persuade Sybil about the woman in the guest's room, the shadow of a boom mic appears on the top wall.
Visible crew/equipment: After Mr. Johnson refers to the Torquay guide as the 'world's shortest book' and leaves the hotel, you see a boom mic coming in at the top of the screen for about 3 seconds.
Answer: It's "Leisure Complex" by Dave Gold and Gordon Rees. Can be found on YouTube. The relevant clip is around 25 seconds in.