I'm not sure what I'm after, posting about this - I suppose I just wanted some other opinions!
We moved into this semi 10 years ago. The houses on this road are arranged in sort of C blocks (god that sounds like a prison! 
) so some are right on the road and some are set back. Ours is set back from the road and accessed by a footpath that serves 4 other houses (it sort of branches at one point. Yes I do need to draw a diagram, I think). The NDNs that we're joined onto are also set back from the road. We are not concerned with them here...
Our other NDNs, we are not joined onto (semis, remember) and their house is aligned at 90 degrees to ours. Their front gate is also served by this footpath from the main road.
They have lived there forever (think the man actually grew up there, back when all these houses were council houses. There are about 20 and I think the council/HA now retain about 5 of them - all others are privately owned, including ours and these NDNs). The guy who lives there is VERY self-assured about his rights and so on. He claims that back in the day, a public right of way path used to exist - it ran from the main road, followed the existing footpath serving these houses and continued through our front garden, running between his boundary and ours but within our boundary IYSWIM, and then into his actual garden, then down what is now his drive and out the back onto the access lane. (an additional wrinkle here is that many of these houses are accessible by car only from the rear. Ours and his are two of those and we have long driveways the length of our back gardens, which feed onto a back access lane.)
NDN Guy has always been mildly belligerent about this old right of way and claims that it still exists, even though no member of the public would now use it, since it ends at his garden fence! He says it's on us to keep it clear and make sure he and his partner can get onto it in order to trim their various shrubs and vines that climb their fence, and that they have every right to do this without asking us. They DO sometimes tell us they're coming into our front garden to trim things - but make a BIG point of saying 'this is just a courtesy to you, because of course this is a right of way' 
NDN Guy says that ages ago (eg before our time) he bought a thin strip of land off the council that, because of some odd foible, they still owned and which ran down his driveway at the back, and was therefore able to make his driveway a) wider, and b) private. He says by doing this, he closed off the public right of way at his boundary line, BUT that since it still runs across our front garden, he and his (annoying) partner can still pop in any time they like, without notice.
I do try to get on with him. He's basically friendly but does like to fiddle about in his garden and is never still. Hence all the trimming, etc. He is v long-suffering because we 'are no gardeners' (in his words) and basically have a long strip of grass and a couple of trees out the back (none of which overhang his property), plus a tallish hedge that screens the boundary between his house and ours. This is sometimes a point of contention because we let it grow fairly bushy (the birds like it) and he wants to be able to see over it from his upstairs windows to the View (which is nice). We know he has no right to a view over our land but hey, we try to keep the peace, so it gets a good prune most years. He also doesn't like the hedge because it runs along this mythical right of way and means he can't access it as easily as he would like to.
So. Not even sure what I want to know. Is he BU? Are we? Is that even a thing, a right of way that hasn't been exercised for probably decades apart from by him? Can it still be a right of way if he actually blocked off one end of it? Does this potentially make our property vulnerable in any way, in the future?