start on the b4017 near cumnor at the north side, of the entrance to bradley farm in line with a row of chestnut trees along the farm drive. go north for 377 yards to the slip road with the a420 and turn left. (sign), 0.214 go down the slip road to join the a420 westbound (care of fast traffic from right. warning sign). continue to the a338 roundabout and take the second exit to continue along the a420. (sign m1), 2.482 continue to the large roundabout on the kingston bagpuize by-pass. take the second exit to continue straight on along a420. (sign, m2, m3), 5.623 turn around the a420-a417 stanford road roundabout at the top of the hill before faringdon and take the third exit to return eastwards on a420 (care). (check sign m4, m5), 13.221 continue to the kingston bagpuize roundabout and take the second exit to go straight on along the kingston bagpuize by-pass. (m6, m7), 20.770 go straight on along a420 at the a338 roundabout on the next stretch of dual carriageway in tubney wood (sign), 23.925 continue on a420 for about a mile more to finish at the drain at the extreme eastern end of the lay-by opposite the road to wootton and just past the greyhound pub at bessels leigh.