The Pettit family who lived at Spring Valley Mill played themselves in the film. Harry Pettit Sr (the father in the film) was a freelance artist and naturalist, and illustrated Malcolm Saville's novel on which the film was based. The real name of Spring Valley Mill was used in the film.
Side-by-side photographs of Harry Pettit dressed in Royal Navy uniform and of a boat at sea were used to imply that he had lost his leg while serving in World War II. In fact he lost it before the war in 1932 when he jumped off a moving train and fell under its wheels.