(Century 21/ITC scifi series, 1970-1)

Episode 1.22: Confetti, Check AOK
A London Country AEC Merlin/MCW passes the Caledonian Hotel in Watford (thanks David Boxall):

Episode 1.26: The Long Sleep
Tinted flashback scenes at London's Piccadilly Circus feature London Transport AEC Routemasters on routes 13 and 15, a Green Line AEC RF, and an East Kent AEC Reliance/Park Royal coach: