We used to explore these tunnels during the school holidays around 1953-55. I don't remember them being very big, certainly not 2 miles.

Me and a mate explored them around 1962/3 I remember two entrances before our torch batteries faded. Huge bomb proof steel on two entrances we found.

Yes Tony the configuration seemed a bit different as well. From my memories they carried on further than the one parallel to the cliff but and further along there were others coming back towards the cliff face. When we first got in there we across main passage and because I thought it was a dead end but looking at Clives map Ididnt discover the second main passage. As I said our torch batteries were failing as we got near the second entrance/exit but I see it extends even further along the length of the hill. How Id love to explore again , but Im told it is all sealed up.

I got into these tunnels around 1975 with the friends I have vivid memories of crawling through a small hole..then on your right was a guard room and in front an archway with "mind your head" painted on it which then opened out into the larger tunnel very much like your photo!