Ok, my advice to you would be: (as a studier of Monty Roberts theories)
Next time you go to bring your horse in, try this. Be the Alpha of the relationship. If your horse has gone for you in any way and you have retreated, he has automatically learnt that that is positive behavior from his perspective because he got the response that he desired.
Leave your head collar at the gate and go in 'unarmed'. Remember this: wherever your horse is, is where you want to be. That patch of grass that he is grazing on, or that tree he is standing under, is where your want to be. So you want to move him, like an alpha horse would move an underling. Make yourself big (walk like a cowboy with your elbows out), look him straight in the eye and chase him off. Don't make any noise and don't wave your arms about unless he refuses to move. Stand on the spot that you chased him from until he stops moving and notice his response. He will look at you with ears pricked and a 'what on earth are you doing' look on his face! This is good.
After a minute or so, chase him on again. Repeat this 3 or 4 times.
On the last time, stand still on the spot that you chased him from and make your self unthreatening. Relax your shoulders, drop your eyes to the floor. He will generally turn to face you.
Walk towards him in a slow manner, with your shoulders and eyes down. Walk as if you are approaching his shoulder. He should stand still and allow you to advance. Once you are with him, give him a pat on his forehead- keeping your eyes off his. Now walk away towards the gate and he should lock onto you and follow. Once at the gate, offer his headcollar, let him have a sniff and then put it on him.
If he doesn't lock on- keep repeating the above steps until he does.
Trust me, I have used this technique on dozens of horses and it works.
I would definitely suggest you try using join-up as part of your training, as horses with bad pasts really benefit from it. After all, you are talking their language!
Good luck and if you want any more advice, please PM me as I would love to help.
