One member of this fleet, No 420, holds the land speed record for a regular service bus, having achieved 80.82 mph under test conditions in May 2015. It carries a special cow print livery reflecting the fact that the compressed natural gas is, at source, methane derived from cow dung. Buses (701-705) used on the Royal Blue 33 route, are the first CNG-fuelled double-deckers these feature Enviro 400 MMC bodywork. Bus 703 being named the "Richard Wilding OBE". In 2018 a further 17 (706-722) CNG-fuelled double deckers arrived for Purple 17, unlike the previous order for CNG Buses these are fitted with Enviro 400 CITY bodywork.