Desert Island Discs would have been on the Home service/Radio 4 for the whole time the Marlows books are set. Which of the characters would be famous/interesting/ notable enough to be guests? What do you think they would chose as their luxury? What about their book? Which records would they chose? With the Marlows, there is the added advantage that they have lived through such a stretch of time - 1940s to 1980s that there is a great deal of music to choose from.
And how would Patrick cope with all that music?
I discovered in the course of making a list for Lord Peter Wimsey on my own journal that links to youtube clips were post-able in the post, but am not sure about in the comments. That's assuming anyone feels like playing, of course.
To start thinks off. I'm pretty sure famous actress Lawrie Marlow would choose this as one of hers:
https://www.youtube.com/watch?v=h1xO7RwTV4k I've got an omnibus copy of the Hornblower stories Nicola can have if she wants...