This is a funny one...
the way I see it (of course insurance and recovery companies see it the other way) a green lane is just a road like any other, only difference is its an unsurfaced road..
but still...a road!
to drive on green lanes you need insurance, tax and mot and be fully legal, just like on any other road.
So it shouldnt make a difference...
but if you call the recovery service to get you from the middle of salisbury plain (even though you are on a green lane) they'll be likely to say you are off roading and wont recover you..