During the DVD commentary for The Thick of It (2005), Peter Capaldi states that his appearance in this episode of Poirot (1989) yields him the most frequent repeat fees of all his television appearances due to the programme's high overseas sales.
Molly's car is an MG Type TA Midget. This model was introduced in 1936, and 3,003 were produced between 1936 and 1939.
Hilary Tindall's final screen role.
Hastings is reading Amateur Photographer #2434 (July 3, 1935).
The large sculpture in Claude Langton's studio was very likely inspired by Tatlin's Tower.