Tom Leppert used to tease me about this; every time I saw him he would bang on about how good it was, yet would never reveal where it was.
I was watching a Krautrock documentary on BBC4 and there was a very good section with an interview with Michael Rother of Neu! (and ex-Kraftwerk). The interviewer asked him what his inspiration was for the Motorik sound that was the hallmark of their music and he quoted three sources. The German Autobahn, machinery and the River Bollin in Wilmslow..... I coughed up my beer and rewound Sky+ to check I wasn't imagining things and I wasn't. A check on t'interweb reveald that Rother lived in Wilmslow during most of his childhood. Perhaps Hallogallo is inspired by this fragile sandstone mystery?