Thanks for your reply.
There is no time limit involved when looking at whether a right of way ceases to have effect.
Generally once an easement or right of way has arisen it will continue indefinitely unless it is extinguished or released, either by express agreement of both parties or the party with the benefit of the right of way has taken some positive action or step to abandon the right of way. The mere blocking up of a wall, for example, is not necessarily an act of "abandonment".
A right of way, a sstated above, can be sometimes impliedly released by the owner’s actions or in rare cases by the owner’s inaction. It can on rare occasions be established that a right has been abandoned. However, this is a not easy to establish as at law there is no obligation on a party to exercise that right. Failure to do so will not automatically result in an easement or right of way being released due to the assumption that it has been abandoned. If the owner explains the non use he or she may still be regarded as not having abandoned the right. Failing to use an easement or right of way is not of itself sufficient and abandonment will not be inferred. The owner must make it clear that he or she is abandoning the right not just for himself but also for his successors in title.
In the case of Benn v Hardinge (1992) 60 P&CR 246 the Court of Appeal said that the failure to use the right for 175 years was not enough on its own to indicate an intention to abandon.
There is an assumption that the right has been abandoned where it can be shown that the original character of the dominant land has been changed to such an extent that the right of way has become unnecessary or impossible to exercise.
However, this is only a presumption and can be rebutted by the owner producing evidence to show that the original character of the dominant land can be restored at a later date and that the need for the right would be revived (ie in your case, by now wishing to use it for a means of escape).
This is a complex area of the law but from what you have told me, the right of way still remains in effect. You should perhaps speak to a local Solicitor, who could write to your neighbours explaining the law.
I hope this helps. If so, I would be grateful if you could rate my answer.