but the 1972 edition – featuring a goose that the cast are chasing for Christmas dinner – exists in the Thames Television archive, which is now owned by FremantleMedia. Reg Varney undertook a PCV driving test in order to be filmed driving the bus for the exterior scenes. The earlier series were recorded at London Weekend Television's original studios in Wembley (later Fountain Studios). In late 1972, LWT relocated to new studios on the 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 an upper deck was lowered from a lighting rig. Filmed external shots were part of the series. LWT arranged with the now defunct Eastern National Omnibus Company to use its buses at Wood Green bus garage in North London. They were shown as belonging to Luxton and District. Luxton is supposed to be in Essex, and actual Essex towns including Southend-on-Sea, Basildon, Braintree and Tilbury are all mentioned. One of the bus route termini was "Cemetery Gates", for which LWT used the entrance to Lavender Hill Cemetery. A different Lavender Hill in Battersea also features in the last episode of the last series, featuring the town hall (now the Battersea Arts Centre). The fourth series was affected by the ITV Colour Strike, with seven of the 13 episodes being made in black and white. Characters from On The Buses appeared in two other series. A spin-off, Don't Drink the Water (1974–75), ran for thirteen episodes, featuring Blake retiring to Spain with his sister Dorothy (Pat Coombs - who also played one of the female bus drivers in the first On The Buses film). Anna Karen reprised her role as Olive in LWT's revival of The Rag Trade, which ran for two series in 1977–78. Theme music The theme music for the series, entitled "Happy Harry", was written by Tony Russell. Featured buses The red Town & District buses were Bristol KSWs with Eastern Coach Works bodies. These were former Eastern National. Stan's and Jack's "regular" bus appeared to be VNO 857. The green Luxton & District buses were Bristol Lodekkas with bodywork by Eastern Coach Works of Lowestoft. In reality these were Eastern National buses (in some episodes buses could be seen with Eastern National on the