I think the closure of a right of way has to be sought by the owner of the land it crosses and I believe the term is an 'extinguishment order' or something like that, that term seems to stick in my mind since my time on a LAF. I do not have a great ability to follow legal nitty gritty, because as a person, who has had more success in creating stuff, negativity does not seem to stick in my mind as much as positive lines of thought.
The big danger, I sense, is in the fast tracking that has been agreed for opening up 'lostways', since the demise of the lostways project and the 'Stepping Forward' initiative. I suspect that closures of seeming unused rights of way may well be given the same fast tracking as the re-establishment of lostways. The British notion of fair play despite the deliberate corruption of the definitive Map by the forefathers of todays landowners.
So often the important part of a notional lostway (say X2Y) may be a little used RoW (Y2Z) some distance from it, if there seems to be a continuity of way created by the lostway and it further links into the access network (W2X) we come up with W2X + X2Y + Y2Z = a much increased distance of multiples a lot greater than 3.
English Nature suggested that 10% of our access network could have been lost to lostways but a more imaginative view of lostways could well show a far greater gain to our access network.
The Lostways Project by English Nature only investigated the legal strength of available proof to recover lost ways, they did not look at the political corruption that created those lostways or the value of an access network that might have been with their inclusion.