A mistry solved ?
We found a strange pile of what looks like leftovers from a lathe machine. it was found at the end of the longest part of the tunnel which was a strange place to dump it. Simon who visited us on the 7th has provided the most plausible answer so far. It may well be the shield or armour from a reel of armoured cable. We already think that the tunnel was used for storage at the very late stages of the war and have already found some parts from bunkers etc. So chances are this reel had its cable pinched post war and all that is left is its armouring shield.