Go back on foot along the road you just traveled up to a clearing, at which point you will walk uphill in the woods along the track that goes directly between the boulder stones and fallen trees. Climb straight into the woods along the path until it begins to bend to the right. Cross a moraine deposit (cairns - you can just make out the crag) and walk below the wall.
Approach: about 30 minutes steep walk from the car park.
Warning: do not park along the road as parking there is prohibited.