The Renault 5 driven by Berenice is actually 2 different cars. The first vehicle used was written off and a second identical one had to be found and bought during the shoot.
In Brian's garage there is a wheel clamp which was used as part of the set dressing after it was removed from a crew vehicle. The van in question was immobilized by an illegal group of clampers in London's east end.
The snow seen in the latter part of the movie was completely unexpected. The shooting schedule was re-written in order to film exterior chase and death sequences to great effect.
During the post production process the company computers were seized by the bailiffs. A couple of vital scenes and the majority of the soundtrack were lost. The film was completed by piecing together what remained on laptops and from earlier recording sessions.