For full information, please see Puzzle Cache "The Chalfont Challenge!" (GC6BP81).
Follow the path Northwards. Don't worry, no keys or codes are needed for this one. While in the area look for an Old Screw Plough hiding behind some over growth! I wonder how long that has been there for?
As good practice, please bring a Pen/ Pencil, a pair of Tweezers, Carrier/ Rubbish Bags (CITO), a pair of Rubber/ Latex Free Gloves maybe, and your stealthy mode!
Watch out for muggles as they can be abundant around here I hope you enjoy these and I hope they don’t stress you too much.
Good Luck