Premise: Cowardy Custard is a musical revue and was one of the last Noël Coward shows staged during his life. It was devised by Gerard Frow, Alan Strachan and Wendy Toye. A book, also titled "Cowardy Custard", was published in connection with the revue, similarly celebrating the Coward image.
Hypothesis: A book called "Cowardy Custard" was the inspiration for the Noel Coward musical revue, which was one of the last shows he staged during his lifetime.