The screenplay had a different opening to the one that appears in the film. It involved John Cleese waking up to his clock radio, and Cleese seen naked and wet in the shower.
Actress Sharon Maiden received an 'Introducing' credit. The movie though was not the debut feature film of Maiden who had appeared in the earlier 1983 cinema movie Party Party (1983).
The make and model of the car taken on the cross-country trip to get to the Headmasters' Conference was a blue 1970 Morris 1100 MkII [ADO16]. It is basically the same car that was used in John Cleese TV series Fawlty Towers (1975), only with a different paint job. Both cars are BMC 1100s, but the version in Fawlty Towers (1975) was a 'Countryman' - a small estate car (US: station wagon). The car in Clockwise (1986) is a saloon (US: sedan).
When Brian Stimpson and Laura stop the Porsche the driver states that the car was new and had only "12 miles on the clock" After Laura steals the Porsche we see a close up of the tachometer the clock clearly reads that the car has 754 miles "on the clock".
(at around 1h 23 mins) By the end of the movie when Stimpson is delivering his speech and the left arm coat sleeve falls down we can see clearly that is John Cleese himself that pulls something with his right hand making the sleeve fall.