Wonder if that adit could be excavated ? Was it an explosive store ?
They had a supply of grenades and rifles with ammunition. Tales tell that it was permanently manned, and there are the remnants of some old metal framed beds in there, rusted away to almost just an imprint on the floor now.
A very fragile rifle box and a few other items such as coffee tins etc still exist and they too are also very frail.
An interesting place but not at all extensive.
"You Chinese think of everything!"
"But I''m not Chinese!"
"Then you must have forgotten something!"