The Scottish location, Ardverikie House also featured in Monarch of the Glen, The Crown, Outlander, Mrs Brown, Salmon Fishing in the Yemen, Outlaw King and the James Bond film No Time To Die.
There is a discrepancy in the story regarding when Miss Blacklock quit her job. Miss Blacklock states she left Randall Goedler's firm when he died, but Belle Goedler tells Inspector Craddock that she left to take care of her sister when their father died and Randall was furious.
This adaptation omits the novel's supporting character Sir Henry Clithering, though he is briefly mentioned.
Kevin Whatley plays a Detective Sergeant, assistant to a Detective Inspector, a precursor to his role as Inspector Morse's assistant.
Although the Harmons' cat Tiglath Pileser is a male in the novel, she is a female named Delilah in this adaptation.