Charles Hawtrey was unable to drive, and was given 1 hour lessons 3 times a day for 3 weeks by Pinewood Studio staff and passed his test on the Friday before filming began.
The Glamcabs were a brand new model of car from the Ford Motor Company, the Cortina, and Ford's involvement in the film was, on their part, to promote the new car. Introduced to the market in September 1962, the Cortina became a classic of British Ford, passing through five models over twenty years, before its eventual replacement in 1982 was given a new name, the Sierra.
Many of the extras for Charlie's cab company were actual taxi drivers.