There is a cache that has been on my list of 'caches I must find' called The Devil (GC25VW5). It is a puzzle cache, the puzzle answer will take you to the first of 3 micros. Once you have all 3 micros then you can work out the final co-ordinates for the cache. The walk was around Devils Punchbowl near Lambourn, we measured it at just over 6 hilly miles!
This was one of the most satisfying caches we have found and well worth the walk. It is a shame that there haven't been many other finders of this fantastic cache.