Stupid campaign for this telephone directory enquiries service included in summer 2004 an ad shot driving through the streets of London. Several buses are glimpsed, including a Routemaster and a
London United Alexander-bodied VA-class Volvo B7TL
A much better 2009 ad uses the 'Ghostbusters' theme (who you gonna call?) and brings back Ray Parker Junior to sing it, in various guises, including a bus conductor:
The Routemaster in question is RML2509 (JJD509D) in Metroline livery and part of the Michael Harper-Smith collection in Los Angeles: