The Subterranean Saturday event last weekend organized by the London Fortean Society was a resounding success. All 400 seats for the Conway Hall had sold out by last Thursday and the place was rammed. I think my talk on secret tunnels went well (certainly a bigger crowd than my first out-of-London book talk last October when I attracted an audience of 7 - four of whom were my wife, her friend and our children).
There's some great feedback on Twitter here.
Even more impressively I sold 60 copies of Secret Tunnels of England: Folklore & Fact, so there are now fewer than 200 left. Sounds That Swing/No Hit in Camden is no longer stocking the book, but it should still be available from the following: (London) Watkins, Treadwells, Atlantis, Hatchards, London Review of Books Bookshop; (Nottingham) Five Leaves; (Hastings) Albion Books, Borough Wines; (St Leonards) The Bookkeeper.