A piece of graffiti seen during the title sequence reads "Corny is a rotter", an in-joke reference to associate producer Henry Cornelius whose nickname was 'Corny'. This reference was possibly heartfelt as Cornelius was a hard-driving perfectionist.
Felix H. Wilkinson:
Oh, how I loathe adventurous-minded boys.
When the Rhona Davis character is being tied up, a part of the rope goes around her neck. Next shot the rope is lower. Also the amount of rope around her changes after the children discover the letter to her other name, Rhona Watson.
Opening credits appear in chalk on a brick wall on a bomb site.