Thanks for posting these. I just had one doubt when I saw the title of the thread, but I have found nothing on the Internet to indicate that Simpson is no longer with us.
I am away from my books right now but I remember he wrote some of the best poetry of the Second World War, using, like Charles Causley, ballad forms to tell some of the horrific stories of combat. Here's a link to one of the most famous ones,
"Carentan O Carentan" .
David Mason, who wrote a great piece on Charles Causley in the recent
Able Muse, has also got a fine essay on Simpson in
The Poetry of Life.