I'm actually going to look at one this Sunday.. bit naughty pre-epmting Duffy's sale.. but its 5, and it hacks, so my mum will be able to ride too.. 162cm.. so 16.1hh... will get the link- no confo pics though :/
It is a bit hard to tell much from the photo's - they have angled them quite a lot from the forehand, so you can't see true lengths of the neck and back, can't see a true angle of the shoulder etc.
I don't think the neck is terribly long, going by the camera angle it is probably quite a good length in relation to the back. I also don't see a long back.
Maybe a touch over at the knee, but that could very well be the angle and the way the horse is standing, and if there is anything there, I wouldn't think it could cause much trouble as far as soundness and performance goes.
Like Anabel, the only thing I'd be really worried about is the stifles, and if you like him, I'd get those thoroughly looked at.