I had a wander round there this weekend, been meaning to do so ever since I laid eyes on the place but didn't have anyone to go with 'til an old friend visited from Birmingham. We used to do a lot of urban exploring down there back in the day but I moved up to Newcastle a few years back.
We didn't get to see all of it as the dusty, damp atmosphere was overwhelming after a while and we weren't prepared enough for it, but had a good look around the southwest corner where the old gym and the ward with the mural is. It's a real shame to see such a once proud building in such a state. Walked past the Toy Store and headed up the stairs with the broken skylight, found some maintenance documents from 2004 (didn't know it was even open then) and some old coffee mugs.
And then, just as we were heading away from the stairs, my friend called me back. I walked over quickly to find him sitting with a fat little pigeon on his hand, stroking its head! It was completely unruffled and seemed tame as a shrew. We're guessing he's been in the hospital all his life and has never encountered a predator. Anyway, we ended up taking him back to my flat, giving it a wash, some food and a warm bed. Might put him back but it would be a shame to dump him in there again.
Also here's a map. The red area is where we visited, the yellow circle is where we found Mr Miyagi (the white square within it is the skylight, I think) and the green rectangle bounds a really nice field in the grounds that would be great to chill out in during the day and do some cloud-spotting, if no-one minded.