Yes, the film was mostly filmed at the Elstree Film Studios in and around Borehamwood, but the tv series was filmed elsewhere:
The series was recorded at London Weekend Television's studios at Wembley. In late 1972 the show relocated to the company's new South Bank of the River Thames; here the outside doors to the main and secondary studios were too small to accommodate the double-decker buses used in the series. Therefore single-decker buses were used and a plywood mock-up of a second deck was lowered from a lighting rig.
Filmed external shots were part of the series. LWT arranged with Eastern National bus company to use their buses at the Wood Green bus garage in north London. For the series, they were under the ownership of 'Luxton and District'. 'Luxton' is supposed to be in Essex, and actual Essex towns such as Southend, Basildon, Braintree and Tilbury are all mentioned. One of the termini for the buses was 'Cemetery Gates' and for this, LWT used the entrance to Lavender Hill Cemetery in Enfield, Middlesex, near Reg Varney's home.
Hope this helps with your enquiries.
