Well, despite what I've tried to explain to our boss, she's come out with the same spiel as she did earlier.
"I've been buying design for 25 years, and I've always been given the source files. If you didn't give them to the Client you'd never get any work from them ever again. We need to send them the Illustrator files, all layered PhotoShop files and the InDesign files as well."
So, not only are these people now getting my PSD artwork done specifically for a front cover that they can rip apart and re-organise, bastardise, etc any way they like, but they are now getting the InDesign files. So they can tear the entire layout and style apart as well and replace all of our company's copy at the drop of a hat.
Nice.