Bring wellies, and perhaps waterproof trousers. This area is often dense with muggles, so pick your time carefully (perhaps an evening or weekday) or bring along a dog or small child as a smokescreen. I don't recommend trying for it on your way to work.
Please close both the inner and outer containers carefully before returning to the hide - if you haven't seen one of these before, note the way it is sealed before you open it. The environmental camouflage also keeps the cache in place, so please return it to the same spot.
A note from LeHylton:
Make sure to not step on the white-clawed crayfish as they're very rare and Amersham is the only location they seem to grow on the River Misbourne, but don't worry about signal crayfish (dark ones) as they're killing off the white!
Pride for FTF (congratulations Clue 72 with a speedy and joyous find), prize for FTF with child - a small Lego set (brand new but repackaged to fit in the cache). There's also a pack of cards as a possible swappable.