Right, here's the updated version of the map. There's a few changes to the layout, and I've added arrows to show the flow in the pipes, markers to show where the valves are, and a grid reference. The compass directions are arbitary - we've not been given the direction of north. Note that the map appears to tile horizontally - it could even be a disc. We're currently (assuming I've not messed up a turning) in T11.

Map:




Radium: could you check I've not made any mistakes with this map?