Postmans Park

Wonderful spot in the city - read about George Fredrick Watts's Memorial to Heroic Self Sacrifice if you've not popped by http://en.wikipedia.org/wiki/Postman's_Park (no relation!)

Also on my lunch wander I came across the street near St Barts where they filmed the last scenes in Sherlock when he fell of the roof.  Found a phone box there that was packed with fan graffiti and notes stuck in the windows.  It's obviously become a point of pilgrimage for Sherlock fans.