The starting point would be to get a copy of her title deeds (office copy entries) from the Land Registry..The title deeds might have a scale map or refer the the width of the right of way or the size of her garden which either way would show whether they are encroaching or not.This can be done online or through a local solicitor for a small fee
Otherwise, if she is sure that the sleepers are on her land, she can elect to do nothing since the neighbours will have to prove that the sleepers are impeding the right of way. However if the sleepers are on her land they will be unable to show that this is the case.
I hope this helps. If there are any further points please reply
I dont think the width is in dispute as the title deeds are available to all of them. It is basically 4 people against one single middleaged lady and bullying and harassment ( police concur ) are the order of the day. Could you come up with any cases which they might be able to use please
There are no cases they can use, they are trespassing if they drive off the right of way onto her land.She can sue for both trespass and damage to plants etc.
However really she does not have to do anything. I would be inclined to tell them either to put up or shut up.