Well, for starters, hitting him on the head will make him head shy!
secondly, raising the jumps when he is obviously not having a good day is bad. you should just do one last jump to end it on a good note.
also, has his saddle been checked as it looks very far forward in the 2nd pic and if his tack is causing him any discomfort it could cause him to bite while being tacked up.
I think you should really work on your own riding and his way of going on the flat before attempting jumping.
I suspect the weather because it went from sunny and warm to rain...
Actually the first time I raised it he went over it no problem, and secondly I did end it by having him jump 1'6 and left it at that. I've never had him bite me or run out or even so much as not follow a command, so something must have just been off today for him.
have to be toally honest with you, from what you have described he is showing he is in discomfort,
as others have said, he proberly needs that saddle checking,
did you start him off with trotting poles ?
does he work well in walk, trot and canter ?
when was the last time he had the dentist ?
or saddle fitter ?
these are all checks ild do with my horse if she ever showed signs like that
So I popped him in the side of the head
I think what most people are trying to say NightRider that even if your own way works for YOU, it might not be working for your horse, which I think we'll all agree is paramount.
I would not be paying for the services of a RI who just 'let me get on with it' - I can do that by myself!
I think, as others have said, you are in way too much of a hurry to jump. King sounds as if he's in pain somewhere (probably saddle) and you need to have that checked out. He needs to be taught to jump properly, by doing trotting poles, raised trotting poles, canter poles etc. and until he's doing these perfectly and his flatwork is established you really shouldn't be trying to jump him-never mind putting them higher when he's obviously not having a good day. By jumping him too early you will just be confusing him and making him feel that jumping is something he doesn't want to do - as you experienced today when he was running out.
You must also take into account that it could be your riding thats confusing him, get lessons with a good instructor to help you both improve.
And as for "popping him round the head", that is no way to behave towards your horse, you'll only make him headshy.
Good luck anyway.
Maybe he's changed shape though?