Doreen Mantle is credited alongside Richard Wilson and Annette Crosbie in the title sequence. This was the only occasion in the show's ten-year run that another actor received top billing alongside Wilson and Crosbie.
The digitally restored print of the episode, broadcast by the BBC in 2023, was dedicated to the memory of Doreen Mantle, who passed away that year at the age of 97.
Mrs. Warboys praises a few TV detective shows, including Poirot (1989). David Renwickhad written several episodes of that series.