"The Lonely House" (1957)
The IMDb short blurb says "Scotland Yard investigates a marriage brokerage service where the clients have a high mortality rate.", which slightly undersells this GORY tale.
Let's just say you'll never look at potholes in the road in the same light again.
Apart from Ludovic Kennedy as T.V. Newsreader on'telly very briefly, no one of any note, and no "big toe wiggling" in the morgue.
Quite enjoyable.