A few links for you dealing with POW'S :
As a resident of Portsmouth I can remember that when I was younger we still had a Hulk in the harbour!! I believe it was used as a training ship for cadets up till the early 70's.
You can still see some wall paintings at Portchester Castle on the outskirts of Portsmouth. I know that the prisons on the Isle of Wight and on Dartmoor were originaly built to house Napoleonic prisoners. One of the main experts on this subject is Paul Chamberlain.
Portsmouth Napoleonic Society