Dream Demon (1988)

As her marriage to decorated war hero Oliver draws near, well-heeled Diana moves into an apartment within an otherwise unoccupied, sprawling London house where she starts to experience strange and terrifying nightmares. But are these troubling night terrors merely the symptom of an unsettled mind, or the sign of something far more sinister at work? Hounded by a pair of sleazy journalists, Diana soon crosses paths with American tourist Jenny, who appears to have a strange connection to the foreboding house and its dark past.