A tunnel walk would be great! If its helpful I can email you a screen shot of the map with the track drawn on (done using my phone so a little rough but probably better than my fescription). Do you have an email address I can send to?
Hi. Where Lady Musgrove Dr does a 45’bend right then left again just before Bald Hill there is a track that runs straight across the hillside on the ocean side of the hill avoiding the road altogether. Walking from Otford Lookout there us a path on the ocean side of the road behind the barrier and this other track runs off that.