Script versus short story
Some elements are added to the original story, but for the most part, Exton stays true to the words of Agatha Christie and creates a faithful adaptation. The additions include the introduction of Miss Lemon (who tries to persuade Mrs Pengelley to come in) and Japp (who investigates the murder), a fitting subplot between Poirot and Hastings on pancreas exercises, digestive systems and Oriental food (picking up the thread from the previous episode perhaps?), a short visit to the dentist office (implied in the story), and a scene in which Miss Lemon and Hastings attempt Chinese fortune telling. Some plot elements are visualised quite well, like the funeral wake, the exhumation and the court proceedings. There's also a slight change in the denuoument scene, in which Hastings get to draw attention to the two men outside the window (a task assigned to Poirot in the story), and Poirot doesn't give Radnor a 24 hour start after all.
Directing, production design, locations, soundtrack
Bennett competently utilises the location (Dunster in West Somerset, see photos here and here). There's also a nice overhead shot of the three umbrellas as Poirot, Hastings and Mrs. Pengelley meet in a rainy park. The attention to detail is incredible. Peter Haining describes how the area was dressed for the shoot: 'The high street was closed off for a weekend, the numerous gift shops camouflaged and all modern signs removed. Lace curtains were even specially hung in the windows of several shops to create the illusion of private houses. (...) In addition, forty local people found themselves work as extras for the crowd scenes' (p. 51). The soundtrack is quite effective (again, I think we have Fiachra Trench at work), but it has not been released on CD.
Actors and characters
It's nice to see Poiot upset again (note: for anyone who complains that he was never upset until the last couple of series: you should have a second look at some of these episodes!), lamenting the unnecessary loss of Mrs Pengelley and the imbecility of his mistake. There's also his anger towards the doctor. Hugh Fraser once again gets to display Hastings's weakness when faced with the opposite sex. Of the guest actors, Amanda Walker (Mrs. Pengelley), John Bowler (Jacob Radnor) and Derek Benfield (Dr. Adams) all portray their characters effectively.