Michael Removing two dozen slates makes a gap comfortably big enough to take a man and incidentally exposes the timbers. There's no question of how to anchor the rope this time. "You realise we're probably invalidating Finchby's building insurance." Klempner whistles in. "What a shame." We peer down into Stygian darkness. "How far down you think? Twenty-five... Thirty feet?" "It can't be more than that if the windows outside are anything to go by." This time on the rope, I'm much more in control. It's a straightforward climb down, the rope snagged by hand, thighs and crooked around one foot, and my body mass working for me rather than against, hand over hand, I descend into gloom. As my feet touch floor, the slight noise reverbs with the feel of a large empty space. Blind-sighted in