Part of a series of caches exploring a beautiful and out of the way area of Buckinghamshire forest. You may well see deer and horses on your travels, and quite possibly mountain bikers who race in the area.
Collect the matched letter and number printed in each cache in this series to locate the bonus cache.
You're looking for a film canister. You do not need to leave the forest - no need to go near the railway.
Well done GoldenRanger for a remarkably serendipitous FTF.
V'q yvxr gb fnl gung guvf pnpur vf nyzbfg fglyvfu.