From 1991, "The Tragedy at Marsdon Manor" is an excellent Poirot, with he and Hastings headed to meet a man who has a case for them to solve. When they arrive at the hotel where they are to meet him, they learn he has a case all right -- his own. He's written a book, has written his characters into a corner and wants Poirot to help him come up with an ending. Poirot is livid.
However, a real case does appear, that of the death of the owner of Marsdon Manor, Jonathan Travers. He was suffering from an ulcer and is found dead. His wife, Susan, insists that he died of fright and that the grounds are haunted by the ghost of a young woman who was killed there. In fact, Mrs. Maltravers is terrified and keeps seeing her sitting in a tree. It looks like a good case for Poirot.
Really delightful, with Poirot visiting himself in the local wax museum and also visiting a doctor to learn about the late man's condition. When he announces his name to the receptionist, she tells the doctor, "Doctor, there is a gentleman outside who is suffering from Hercule Poirot." With Suchet as Poirot, there is no such thing as suffering.