Both Scott Jacoby and Sally Thomsett were substantially older than the early-teen characters they play.
Chris makes a reference to Roger Tunnell as the Galloping Gourmet of France. Galloping Gourmet was the title of Graham Kerr's television cooking program and became the name with which Kerr marketed himself.
First-billed Patricia Neal does not appear for the first half-hour of the film. Her strong performance is contained in three key scenes, some montage sequences and amounts to no more than about twenty minutes in screen time.
Sally Thomsett had previously worked with Lionel Jeffries as her director in The Railway Children (1970).
The inability or difficulty in pronouncing the 'r' sound is referred to as 'Rhotacism' but the term is not used in the film, not even by the speech therapist. Indeed, the only person to give the condition any name is Roger Baxter himself when he says he heard it called 'Lazy Tongue' in the United States.