Subject: Excellent.
Author:
Posted on: 2016-04-22 09:21:00 UTC
If you can get a time from Teh Nurds, then we can arrange to meet about an hour previously in Trafalgar Square (which is accessed from either Charing Cross or Embankment stations; Embankment is on the Circle Line, so it's a lot easier to get to, but a slightly longer walk); I suggest the base of Nelson's Column, on the principle that it's very hard to miss.
Though if they say 'we rise before the break of day! Forth to the South Bank ere six o'clock has passed!', we may have to rethink that.
hS
(PS: I'm assuming you'll/they'll be walking from Westminster to Tower Bridge, rather than doing it backwards; if you/they plan to do the latter, I'll have to recalculate.)