The film was colour, shown in the 1990s on Sci-Fi channel in the UK. It may have been an episode of Ray Bradbury’s Theatre.
I remember a scene whereby a man and woman are trying to escape an island, I think in the middle of a lake. They were being chased by two immature adults who were dressed and acting like children.
The female chaser had pigtails and a red/white gingham dress and her hair was bunched at each side like two ponytails. The male doing the chasing had on blue dungerees and a yodeller’s hat, they were brother and sister both in their 30s/40s. They had squeaky childlike voices, and ran after the man and woman trying to kill them. It was downright creepy.
Any ideas what it was?