There is a horror movie (color, 90s/2000s, English) about a group of movie actors who go to a rural setting (possibly Scotland/Ireland) to film a movie. There is an old woman and a strange man who run the place they are staying in. There is some sort of lore the old woman speaks of. The heroine ends up at the end of the film discovering a series of tunnels/caves where a pregnant woman is chained. There are psychodelic sequences scattered throughout the film in times of stress…I think including when the heroine is killing or trying to kill the captor/murderer.