The map of Oakley Park shown at the beginning of the movie is in fact that of Banbury, Oxfordshire.
It states in the main titles "and introducing" Elizabeth Seal, but it's her second movie, her first being Radio Cab Murder (1954).
Both John Mills and Charles Coburn won best-supporting Oscars.
It seems the police are so keen to solve the murder their drivers would qualify for F1 drivers today!
Barbara Bates was 17 years younger than John Mills.