The Legend of Grey Wethers

Out on Sharpitor heading for Leather Tor on Thursday and came across a letterbox (not supposed to be any on Sharpitor right??). It was the Legend of Grey Weathers stamp, didn't know anything about it at the time but later found the stone circle on the map and have looked up the legends. I don't have any coordiantes for the box as I'm not good with a compass doh (plus rainy and with impatient kids).

It's not in the book that I can see so may be considered lost but wondered if anyone knew anything about it or why it would be at Sharpitor???