Made me chuckle a few times reading your post as I know it all too well living around here.
It’s a bit of a catch 22, ROWs and bridleways are sometimes really poorly structured, badly signposted and oftentimes don’t link up very well. As a result (have done some pest control work for farmers around here) you will often get a lot of frustrated tourists or walkers who say F it and just trapes across farms, I was on one farm a few years back doing some pest control work and I literally watched 4 walkers push and hack through a hedge and start trapesing across the crops to the nearest gate, as a result there is lots of “get off me land” farmers who immediately get up in arms about it instead of actually spending time signposting stuff like they should “private land, no ROW” signs etc. In that case it turned out the neighbouring farmer ha deliberately sabotaged the ROW and they’d gotten lost, when I spoke to him about it he complained about the sheep being in lamb in that field and not wanting them spooked by any walkers with dogs which I appreciate but also know he went about handling it the wrong way.
On the other hand, a lot of them aren’t helping themselves as they put these “private land, no ROW” signs up on legal bridleways and other routes to dissuade people entirely, I’ve come across a few routes I’m very familiar with, with a new tenant farmer moved in, the public bridleway sign removed and a padlocked gate erected with barbed wire and a private land sign.
It’s like eveything else, some farmers are fine as long as you comply with the rules and show respect when crossing their land, others are utter complete dheads who want no one on their property, legally or not.