www.tuffaboots.com they have a big selection, i have the dartmoors,rear zip fastening quick and easy to put on/take off. [esoecialy for me with bad hips and knees] super comfy from day one had mine 14 month worn every day only boots i ride in, a quick wipe over and they are good enough to go to the pub in,they are nutbuck ,tuffa recommend nikwax this gives them a super polished shine, and waterproofs them, worth every penny.
I have Ariat short riding boots and mountain horse yard boot. The MH have outlast the Ariat 3 times over despite being worn all day everyday, far more comfortable too
I should have clarified that for the Ariat it has to have the ATS footbed or better for me (following lots of fractures in my left foot 30 plus years ago).