Hastings Battlefield and the 'Right to Roam'

Later this year I will be guiding a tour of the "traditional" Hastings Battlefield. It will be a walking tour with about 5 - 7 clients.

The route is pictured below...

The starting point is shown with a pink star.

I want the tour to start at the lay-by on the sunken road now called Powdermill Lane as I reckon this is near to where the Duke's cavalry mustered in preparation for the battle and the lay-by makes a convenient drop-off point for the clients' transportation.

Like many sunken roads in southeast England, the northern edge is bounded by thick, unmanaged bocage which is impassable on foot.

So I propose to head 50 meters southwest to where there's a passageway through the bocage. This is gated, but there's enough room for people to pass around the side of it. As shown on the map above there's about another 25 meters to pass on this property before reaching the battlefield proper. I will have purchased all the requisite battlefield tickets in advance.

Does our right to roam extend to this situation? Or more practically, is it really necessary to find the owner and get permission to cross this property?

Note: no interest in the recent archaeological findings that place the battle elsewhere; that's the subject of a different question.

Other 'right to roam' question(s):