The background paintings/digital art images are art works produced by Mol Smith a digital artist and the writer and producer of the film. His work can be discovered on various internet sites and in art books he has authored.
The film is inspired by books written by Dennis Wheatley, (8 January 1897 - 10 November 1977) - an English writer whose prolific output of thrillers and occult novels made him one of the world's best-selling authors from the 1930s through the 1960s. Of note and also made into a film is 'The Devil Rides Out'. His books have recently been republished by his son.
The scenes in the Caravan were very long sessions often in the pouring rain. A temporary shelter was constructed next to the caravan for actors already made up to shelter under until they appeared on set (in the caravan). Within a few hours, the shelter started leaking as the rain was torrential. The director (also first shooter) often sat for many hours without moving in a very cramped space to film scenes inside the caravan.