There is a cache at the given Coords, with further instructions. The Challenge is only available during the hours of Darkness! Please ensure that you have adequate warm and waterproof clothing for the challenge, as it does get very cold at night, even in the Summer. Also, you will need to have good vision, or have your glasses/contacts available.
You will need, or may find useful:
Basic list:
Torches, means of communicating/signalling (ie Mobile Phones or Walkie Talkies).
Possibly useful list:
Maps, Compass, Binoculars or Telescope, Laser pointer, Thermos flask full of something Hot, Loo paper (just in case), Pickaxe handle (to fight off the Beast of Exmoor/Dartmoor/Wherever ;-) )
This Challenge can be completed without leaving the Public Highway, there is absolutely no reason to Enter any Private property whatsoever.
There are Two prizes in the final hide, for the FTF.
Good luck.