Sorry, this is long!
I’m at a loss about how to move forward with my welsh D gelding. I’ve had him since he was 2, he was lovely for the first couple of years, was still entire until he was 3 then cut, then broken at 4. Was babyish but well behaved, willing and listened, fairly sensible for a young horse. Turned away over the winter and brought back in at 5, which is when the problems started.
He literally turned in to a different horse, is very reactive and over the top spooky, jumping at nothing, snorting, planting, trying to shoot off (I know D’s are dramatic, my other horse is half D and I broke him too, but this was something else). I would describe him as a ball of tension, he’d fling his head up, set his neck and feel as though he was about to bolt.
Sent him away to a professional who did a good job but still v tense all the time. For the last 2 years I’ve been taking him out to shows in-hand and he’s now brilliant in the ring in-hand.
His behaviour was slowly chipping away at my confidence and I dreaded riding him because he’d get tense then I’d be tense and it was a vicious circle. As a last resort I put him on Equifeast in May and it really made a difference, for the first time in 3 years I was able to ride without spooking or tension. He was coming along great, having lessons and even took him to a dressage test, until 3 weeks ago.
Took him to a weekend show, somewhere he’s been before, and the old him emerged as soon as we got there. He was so ott that he almost broke my foot leaping away from something and landing on me. I was in tears that evening because it felt as though all my work was for nothing. A friend helped me lunge him and he was a little better, but the tension was still there. I was going to take him in a novice ridden class but couldn’t due to his behaviour. He was good as usual in the in-hands.
Since then the old him is back. He’s decided one side of the school is terrifying and won’t go near it, despite being fine all summer. I think the bushes there are starting to lose their leaves and he can see through them a bit, but the over-reaction to this is very hard to cope with.
Last night I thought I’d long rein him around the school, something he normally enjoys, to get him used to the scary side without too much pressure. It was a complete disaster. He was tense and jogging, I asked him to walk and he swung his bum in towards the school, so I tapped him with the whip to move him over (he’s well used to this). He hunched his back and went to kick out so I tapped him again to walk on and he exploded, went sideways and managed to get away from me (never done this before) then proceeded to trot/canter around the school with the reins trailing behind. It was awful, I felt sick watching him. How he didn’t rip his mouth open or fall over I’ll never know. I managed to catch him eventually but he is now convinced the school is terrifying.
I’ve lost all confidence tbh and I’ve been in tears over this. He’s been so good over the summer and now we’re back to not even square one, we’re back beyond that. I feel awful as it’s partly my fault for not being confident enough to deal with this behaviour and I will admit I didn’t handle things very well last night. Part of me wants to sell him to someone who can deal with him. I’m only not at the moment as a couple of people have offered to help me. I’m at a loss as to how to move forward with him. It was going so well and now my confidence is rock bottom again 
He’s had back/teeth etc checked, no problems btw.