Hi & welcome to the forum!
Firstly, just for your future ref, altho it sounds like you got the idea already now... don't forget, we only have your written words to go on, so when you say he's 'evil' & 'naughty', that does give us a certain feel about your 'mindset', so careful how you word things, if that's not what you mean, so you don't get/give irrelevant ideas.
Horses aren't 'naughty' or such, they just learn to do what works for them & quit doing what doesn't work. So along with making stuff clear to him, you need to find *effective* ways of making what you don't want difficult/unpleasant for him, but also ensuring that he 'wins' when he does as you ask - make it worth his while.
I've been riding him bareback in a halter, mostly because he is literally too big for all of the saddles and bits available but also because I want him to listen to me and not a bit etc.. just a personal thing.
As for no saddle, if you're a decent, not too big rider or doing long, hard rides, shouldn't be a problem riding bareback, so long as it doesn't effect your ability to control him effectively. If he knows he can unbalance you & make you ineffective because of it, then it's a prob!
As to riding in a halter, i get your 'personal thing' but remember, a bit or whatever else you use is just a tool, to help teach the horse to listen to *you*. It's not either-or. Bit like those who say 'the dog should just Obey YOU, not do it for treats, they're forgetting that a dog will also do what works for them, and they will learn from either aversive(punishment/pressure) or rewards, what works & what doesn't - the treats, or bit or whatever are just tools, that can be used well or badly, but the animal doesn't listen to them rather than the handler.
Personally, I like to start horses in a halter, and progress to a bit only after they're 'listening' reliably in a halter, so I can then use the bit without any real pressure. BUT if he has already learned that he's stronger than you with a halter, that you can't make him do anything he doesn't want to, you need to find a way of *effectively* controlling him, or else you're just further training him to do as he pleases. So, as he's already learned that a flat halter isn't something he needs to listen to, you could go to a rope one(you can spend a few $$ buying about 6m of quality yacht braid rope & find the instrucs online to make your own, custom fit for him) but I'm thinking now he's learned to resist, you probably need to start with a bit or something... sharper.
when we are riding and in sync, it is stellar - he listens to my legs and my shoulders and I hardly have to ask him to trot and stop and go on the diagonal etc
So, I don't like to assume what the horse does or doesn't know(so often a horse is 'disobedient' because they just haven't been taught clearly or effectively or reliably how to do something), but it sounds to me as if he has learned leg & riding aids well in the past, but - whether recent with you or in the past - he's also learned that he doesn't have to do it if he doesn't want. So the issue is, you need to motivate him to *want* to listen & play your games, and also make it unpleasant/difficult/not work for him when he doesn't.
He's not being 'naughty', just doing what works for him. Put yourself in his shoes - would you do a boring, drudgy job for no/little reward? Think about his *motivation & attitudes* towards what you want of him, what he wants for himself. How can you change THOSE, so the Right behaviours will happen without much effort?
and IMMEDIATELY he walked straight out of the arena doors and had NO reaction to me kicking him or pulling on the rein. I brought him back in - I had to fight him on that - and closed the doors. I mounted him from the ground and before I had gotten on him square he took off cantering.
So first thing first, I'd not ride this horse outside a safe area such as an arena yet, and I would not be cantering yet, until he's reliable - without a 'fight' - at a walk & trot. He knows he's bigger than you, so you need to find ways to get him to WANT to do as you ask. Reward based training works really well, be that treats, scratchies, whatever the horse really likes. And it sounds like you need to start with standing still for mounting.
I'd also *teach* a 'one rein stop', starting on the ground. You need to teach
, not try to force, esp with a horse like this, as you can't (safely at least) make them bend, certainly not make them relax when they get there. So teach this, first on the ground, and you can then take one rein for control to bend him a bit when you're mounting. Then start practicing mounted while still. Then at a walk.... etc.
BUT.... does anyone have some tips on working with TERRIBLE listeners?? he is such a beautiful little boy [/QUOTE]
Break things down & get good at 'the basics' and short, easy stuff first. And rewarding Good Stuff, rather than just reinforcing with release of 'pressure'. And I've found very often with horses who 'don't listen' it's because I haven't been listening to them enough. Sometimes I get on 'auto pilot' and don't notice the small things, that let you know where a horse is really at... until it becomes bigger.