Ah yes, if you run south (or indeed run north from Chatsworth or thereabouts) watch out for the Camphill guys. 500' or thereabouts (
) will put you below the top of the valley and give you a feel for the run without dropping to silly, registration taking levels. The first time you do it I'm sure as I was that you will be filled with complete admiration for the bravery of the guys that did it in the pitch black 60' off the deck at 240mph.