I thought it was a Dr. Who episode from the 80’s, maybe a rerun from the 70’s, though I’ve never found it.
The team is investigating the disappearance of some people in a typical “Keeping Up Appearances” type house. I remeber being conceptually frightened because I was probably around 4 or 5 in age and I did not want to disappear by being turned into a gorilla.
The creepy two-faced lady of the house would put people into a room and turn them into a gorrilla. It was set in a British setting, and the team was offered tea at tea time at one point.