I always remembered it from T.V as a kid, more of an Omen type film, some guy gets his head cut off with helicopter blades at one point.
Also seem to remember Kirk Douglas's arse makes an appearance at one point.
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MIKE: I've got it! Peter Cushing! We've got to drive a stake through his heart!
VYVYAN: Great! I'll get the car!
NEIL: I'll get a cushion.