When parents were buying their first house in the UK, I went with them to look at a few around Oakengates and Trench. One place they liked, we went back to about a month after, but it had slid into a hole. Midlands is like a piece of Emmenthal. A school mate ( who became a miner..and later introduced me to Jezza ) said he'd heard that there were tunnels and galleries all over the place that had been forgotten, just lurking down there to eat buildings and things up top .Reminded him of the CS Lewis story The Silver Chair.