Jimmy Sangster?
What the hell is Jimmy Sangster's name doing in the writing credits?
Sangster is known as writer for some of Hammer's greatest films (and others) from the 1950s to the '70s.
Is this perhaps an indirect remake of one of those? Or adapted from some other work of his (eg novel)?
Enter THE NIGHTTHING THEATRE:
http://nightthing.proboards104.com/