To solve the puzzle simple work out were the photos were taken from by starting at the given co-ordinates. An A4 page to print with all the pictures is available here.
To access Brockabarrow Common it is recommended that you park on the unclassified road (not the A30) at the parking coordinates and then use the bridge to cross the A30.
This is open moorland so the usual precautions should be taken.
Many thanks to Natural England for permission to allow this cache within a SSSI and to Mr Molesworth St Aubyn as the land owner.