OK, my new loan horse is an ex-showjumper, he's fifteen.one and he can jump over one metre twenty. I'm loaning him at the same yard he's been at for the last ten years so he hasn't had the disruption of moving or anything, and he doesn't have any injuries and he's about fifteen so he's not young or green. I jumped him for the first time a few weeks ago (when I say jumped, I didn't put up a jump right away, I just balanced a pole on the jump wings about 10cm from the ground, on account of all the cups having gone mysteriously missing) and I expected him just to trot over it, but the second he saw it he stuck his head in the air and literally galloped tiwards the fence and leapt it almost a metre higher, despite it being basically a raised pole. I came off as I wasn't expecting it, but the next few times I turned him towards the pole, he did the same thing, except after he's jumped it, he just trots away as calm as you like. And a week ago, I was in the arena again, and someone had put a course up. There was five, metre.ten high jumps up but Buster was weirdly calm, being all sweet and responsive as I trotted him between the jumps. The second I nudged him into canter however, he did the same thing and tried to jump one of the jumps, but I pulled him off just in time. Its starting to make me worry, and I really want to start competing him over the summer, but I don't feel confident enough. Any help on whats making him do this and what I can do to prevent this in future??