Central, DLR (via escalator from Bank station), Circle, District and Northern (City) lines; also 10 minutes walk across the river from London Bridge station.
Meet on the north side of the Monument (The tower, not the underground station). This is the side away from the Thames with the tube exit in sight up the hill.
Toilets just north in the traffic island on Cheapside; status uncertain at the time of going to press (50p).
Free water bottle top up 30 yards east.