I've spoken to my neighbour and he's going to let me have a look in the tunnel on his property this week. Our two properties used to form part of one larger property during the war. His is partially above ground and he uses it as a garden store, but by all accounts it's a fairly similar construction to mine - perhaps smaller. Hopefully it might yield some more clues as to the possible purpose of their original construction.
Interestingly, it is located roughly on the other side of the rockface behind my garage.
I've also taken a moment to collate all of the 'shopped images posted on the original thread about Dave and his "Light stick". Perhaps not to everyone's interest, but we thought they were amusing all the same! I've put them all in the previous posting on Dave:
Link back: http://gardenbunker.blogspot.com/2008/06/what-would-dave-do.html