Hi STE Carey,
I'd take a wild guess that when you went into your rant you expected others to round to the call. lol. There's a lot of worthwhile, sound advice on this forum for someone like yourself, but you do have to stop and give a thought to what is for the greater good.
You might want to read up on your own history regarding the Mass Trespasses of the 1930's and 60's, but I believe they were mostly directed at land in public ownership, like reservoirs and national parks.
I do understand your frustrations. In Scotland we have a right of access and can camp anywhere worth camping, the few exceptions being business premises/stockyards/farm steadings and enclosed land with livestock or crops, railways, etc... and too close a proximity to a house! Householders have a statutory right to privacy under the Land Reform Act (Scotland), as does someone camping.
There has always been a general acceptance of walkers and campers in Scotland, to a degree! Of course, there were the exceptions. I've had shotguns waved in my face by shooters, attempts at intimidation by land owners and had my car vandalised by fishermen who assumed I was poaching salmon because my car was parked at the roadside by the River Tay overnight, and I have to admit that wasn't very clever of me!
My first thought however, was to draw a comparison between Ben Alder Estate's (among many others) signs welcoming walkers and climbers to enjoy the estate and wishing them safe passage, and the one-off example of copious signs around the vast expanse of Fisherfield Forest, what used to be referred to as The Whitbread Wilderness, stating more or less that trespassers might be shot.
But these are the rare exception, as most farmers, estate owners and keepers are immensely proud of their land, if defensive, and who wouldn't be? I just wish I had an entity like Ben Alder sitting in my back yard. I discovered a long time ago that the face of the dourest Head Keeper will just light up if the right questions are asked. But dinna cross him by wandering into likely stalking areas during the stag shooting. That's his livelihood!
I discovered recently a beautiful small woodland with a disused woodsman's shelter, carpenter's bench with vises, and enclosed with a dry stone wall. With regard to Scottish Rights of Access, I can go and camp there if I please and there's nothing anyone can do about it... except hassle me during the night, and there's nothing I could do about that in the absence of witnesses.
But why risk putting folks noses out of joint. It's only common courtesy to go and ask permission from the owner on the offer of repair and maintenance. If he objects then it's no use to me and, in my view, would be a great pity and a loss on both sides but I can still do the odd sneaky night's legal camping and he'd be none the wiser.
But I probably wouldn't bother, as I'm too long in the tooth to be looking over my shoulder for someone who thinks I might be casing his house up for a burglary!