I like the idea of a 3l hydration pack and given my ability to fall off/over at moments notice I thought the Attack with its back protection might a smart move but a £65a go I would rather find out if any one out there has used one ?

http://www.deuterusa.com/Attack.html

Not tried that one, but I do have a Deuter 3L hydropak and it's very good, gret features well made comfy and the bladder (made by Source I think) is good too.