Robin Askwith replaced Robin Stewart as Mike Abbott, having narrowly missed being cast in the original television series. Stewart was replaced by producer Peter Rogers, due to his reported poor punctuality on the tv series, which greatly irritated Sid James.
Mike's Morris Minor is still registered as of August 2020 with the DVLA but its color is recorded now as being white, though the car is SORNed and therefore not used on the public roads.
Mike gets married at the end of the film; however, this has no affect on the series, which ignores the events of the film and picks up where the second series left off.
The only time husband and wife Peter Butterworth and Janet Brown appeared in the same film/TV production. They had one scene together set in the back garden.
The house and surroundings here were completely different to the TV series. This film version was filmed in Buckinghamshire, Berkshire and Pinewood studios. Whilst the television series was filmed at Thames television studios in Teddington, Middlesex and the house exteriors in Dukes Avenue, New Malden, Surrey.