Billy. You scare me. I had the exact same location/route in mind. Now stop it.
Valman. the easiest route if not the most interesting.
A102 through the blackwall tunnel, M25 towards Gatwick, at J5(i think, stay on A21(outside 2 lanes) follow A21 round bend,m next exit, signposted Riverhead, follow down to bottom of hill(past school and traffic lights) the Harvester is on the right
See ya tomorrow