In reply to El Cap:
Theres generally a lot of rubbish spouted on Health and Safety law.
When you sign something to say you understand that something is dangerous, all it does is serve as a record that you were there when the centre explained to you it was dangerous. It doesn't prove you understood what was being explained to you. It certainly doesn't absolve them of any responsibilty for your actions.
Additionally under Health and Safetly laws the centre is guilty until proven innocent.
So the centre would have to prove that they had done everything possible to prevent the accident. Very hard to do. Hence the 25% awarded.
Did they provide training? Did they asses his abilities? Did he have to answer a questionaire?
When I used to climb at Pickets lock, you just signed a sheet to say you had read the conditions, that didn't prove that I had read them. When I used to climb at the Castle you had to answer some random questions? That goes a bit further.
That is why the staff tell you to stop doing things they consider are dangerous, it's to protect you AND them.
Now the center will probably get a fine and now be suject to very close scrutiny by the Health and Safety exec, with random visits and powers to shut down immediately if they find anything dangerous going on.