Episode: 3.11 The Winding Cloth
The team investigate strange goings on in London. The episode features stock footage of an AEC Routemaster RML and several other Routemasters in London:
However, the episode is actually shot in Canada. An AEC RT passes an archway in the background of one shot:
In a scene outside and inside a shop described as in 'Camden Town High Street', the same RT is seen parked outside the window. The fleetname is 'Thames Coach Tours' and there's no rear destination blind, although there is one in the nearside box. The real giveaway as to the location, though, is the very odd-looking red telephone box and the distinctly unconvincing policeman: