I have found, in my travels, that English-centric barns can be much more squicky about weight than Western barns. It may be that the type of horses preferred by Western riders (QH, Paint, Appaloosa, etc) make better weight carriers because of their conformation. I can't imagine a normal-sized horse that can't carry 180 lbs!
Part of it is that some people who have never had a weight problem don't have any idea of what can and can't be handled by a regular horse. They've got no experience, so they panic. As well, the H/J world, in my experience, is not friendly to anyone on the larger side due to a heavy focus on style and turnout. Maybe other people have had different experiences, but as for what I have seen personally, I always felt unwelcome in places like that when I was younger.
I would say make sure to call some Western places too, most of them I've found are much more accommodating to heavier riders. You see 200+ pound men riding 14-hand QHs all the time, many of them doing heavy ranch work for long hours at a time. A chunky "bulldog"-style stock horse would have no trouble carrying you, especially since you're an experienced rider. Even some members of the gaited breeds such as TWHs, Missouri Fox Trotters, Icelandics, etc have conformation that is well-suited to carrying weight.
Or you could just do what I did a few years back and buy a mule!