I've been watching the 1980s BBC Miss Marple series with Joan Hickson. I've seen three now: A Murder is Announced, The Moving Finger, and The Body in the Library.
In The Body in the Library actor Frederick Jaeger played Colonel Machete; he is on the original cast recording of Lock Up Your Daughters. Actor John Castle, who plays DCI Craddock in A Murder is Announced, appeared on Broadway in the flop musical Georgy in the part Alan Bates played in Georgy Girl. I kept hoping they would sing.