Wow! Thanks for the fast replys all! Again, due to my severe lack of knowledge of warrior tanking, there's a lot of fairly basic stuff there that I missed, will certainly be getting onto him about switching gems & enchants round to get more HP total. Also, I hadn't realised how badly miss-specced he was, our other tank seems to have an ideal survival build, so i'll prob ask this guy to look into respeccing threat based.
Our healing setup is Paladin, Shaman, Druid. The paladin & shaman are MT & OT priority, whilst the Druid looks after raid healing (we have a lot of melee dps - hence the shaman on OT, CH ftw). Was reading another (similar) thread, and they suggested that Druid healers, with their vast amount of HoT's would be better healers for Warrior tanks, would you recommend switching things around so the Druid is on MT duty?
If at first you don't succeed, shout at the dps.