When Dickie and George are talking on the beach, George brings up Sir Walter Scott. Dickie then brings up the film.
Poster is shown.
A poster can be seen at Mandrake's apartment.
When the Doctor is killed in a dead-end, on the wall behind him there are words 'Cul-de'. Donald Pleasence played the doctor and starred in the 1966 Polanski movie 'Cul-de-sac'.
the film was inspired by it
documentary about the making of "Cul-de-Sac"
The movie clip is shown.