I've just realised something scary about my HMS Amazon. When I was planning the project, I bought a book called 'Type 21', by Capt. John Lippiett, RN. I remember I had to order it in, because it was about to be published, but hadn't arrived in stores yet.
I've just check the book, it was published in 1990. High time I got on with this one.
Cheers
Tony