This cache is not on the ancient Forest boundary of the 1240 Perambulation, but has been placed as a waymark between Cator Common and Wallebrokesfote. More details about the Perambulation can be found on the cache page for the Dartmoor Forest Bonus. On the front page of the logbook is an adjustment to be made to the Bonus co-ordinates, which you will need to find the Bonus.
If doing the Perambulation as a route, the next point on is Wallebrokesfote. From this cache at Riddon Ridge, continue down to the gate and follow the track through Babeny Farm to the tarmac road. Follow this road until it takes you once more over the Walla Brook. Continue past this bridge until you come across a bridleway sign pointing to your right (waypoint below), and follow this down the brook until you reach a clapper bridge. Cross the brook here and continue down to its confluence with the East Dart, which you will need to cross on the stepping stones to get to the next cache.
Note: There is no parking at Babeny Farm, or along the approach road to it.