Brenderups are still made they’re just not sold in the US. I don’t think brenderup is as active in the horse space now but they still make trailers for lots of other applications. Parts are available there’s also tons of dealers in the UK that will ship as long as it’s not something huge like a floor. Brakes, struts, suspension parts, couplers, windows are all easy to get.
The Merhow is fine, though I wouldn’t want 7’2" but my horse can be a giraffe about the trailer and nailed his head on my 7’8" high Xtall trailer more than once. You probably aren’t going to want to tow two horses in it with an explorer. It’s not really the weight it’s just the geometry and towing feel of the whole deal.
I personally wouldn’t let the $3000 be the decider. Realistically, you will be looking to replace the Merhow with something newer/nicer at some point. Brenderup opens up future vehicle options for you and probably also puts less wear on your vehicle (even at 1800lbs, I would bet the merhow’s loaded tongue weight is 400+)