just to clarify one point which maybe of use to you.
if the private road juctions with a public road,
unless it is gated [and by this i mean usually closed]
it comes under the same laws as any public road and police have the same powers, as if public.
i sufferred very badly with several of my farm tracks being used by boys racers to go down and smoke dope.
regardless of how securely i made the gates they are always breached.
having been visited by the local police liason officer
i removed the gates and the police now patrol the area
problem has now gone.
just my 10p
dx100uk