Just a quick update. The experts that visited last night were actually a bit baffled! They said it wasn't what they were expecting to find. They said they hadn't really seen inside one like it before, but thought that the roof was definitely fabricated from German steel (as opposed to British steel seized in France, or French steel).
They agreed that it seemed to have been set up for heavy machinery (or something heavy that needed to be attached to the floor at least) and could have been a workshop, but they were not sure what for. They thought it might have been a very early construction at the start of the war, and that it still may have Luftwaffe links, because apparently the Luftwaffe were based in the vicinity. They also thought that the Lee Enfield guns were probably put in there after the war before it was sealed, rather than have leftovers from the war itself.
Whilst inside tonight took a picture of the (horse-drawn) cart arm...
and also we noticed that the green gunk / paint had now turned orange since two days ago? Deterioration due to change in air quality perhaps? I think that I should start a clean-up and maintenance program for the tunnel soon.
The local experts said it would actually probably help to clear the floor now to look for clues, and that they would go away and do some research through the papers and various archives that they hold. I'll post what they come back with. All in all, they were pleased to have seen it, but said that it raised more questions than answers!
They did say that it appeared to be fit for use, which was good to hear.
Dave decided to stay home and catch up on all the reading. This blog had some 33000 hits in its first day yesterday ! Crazy! Thanks for reading.