The extract Mrs Rich (Claire Skinner) reads to the girls is from Christina Rossetti's poem Goblin Market; about the sexual corruption and awakening of young girls.
Carol Macready appeared 18 years earlier in "Poirot: Peril at End House" as Milly Croft. 1990.
Miranda Raison (Mlle Blanche) would later play Sonia Armstrong in Kenneth Branagh's adaptation of Murder on the Orient Express (2017).
Susan Wooldrige (Miss Chadwick) previously played the role of Amanda Brewis in the Peter Ustinov Poirot production of Dead man's folly.