I met up with Toothdoctor to find the entrance to Lockstock. We scouted a few possibles with no success, then spotted something interesting. Lifting a lid revealed a cobweb topped darkness, a set of rungs brought us into a chamber lined with large winding gear.
A passage lead both ways out from the central section, with a massive penstock gate at each end.
Going down a shaft lead to the sewer level. The A and B Outfalls sewers joined and continued under the penstocks. The setup is used to balance the flow between the sewers and also provide a way of controlling the flow to each interceptor.
The place was covered in rust, heaters along the wall had gone completely brittle. Not Lockstock but close!