Would the local council have any say over how the land is being used in terms of public access? Or is there some other body who would? What about the local MP? Or could the council force him to sell the land the road is on to them?
Contacting the media to see if they’re interested in the story could help too, surely Shrimpton doesn’t want to be seen on the local papers or on TV as being a selfish git.
If nobody has explored these avenues then they could be worth a crack, never any harm in asking. Could be more effective than trying to sweet talk someone who doesn’t appear to have good intentions at all.