Icklepickle : Honestly... having the dentist come out again isn't something we can afford right now, sadly, and it'd be cheaper to talk to a few other people and try out some bits. As for his saddle, that has been properly fitted and most of the time we're riding bareback. He doesn't appear to be sore, we've thoroughly checked him over, so I think it's the bridle thing combined with behavioural.
Alexishristina, I am sure what ever you do is for the best hun:) Have a try with the french link and see how you get on. You never know it could be as simple as bit choice problem:) Have a go at doing some long and low work and making him work through his back, this will get him to relax and hopefully will stop throwing his head:) Let us now how you get on, but by the sounds of it you are doing fab :) x