There's something very similar down on the Embankment (North bank of Thames) near Chelsea, except from memory it's a boy (it's a really long time since I've seen it but I really liked it when I was a teenager)
Just had a look for it - here it is, apparently by the Albert Bridge
http://picasaweb.google.com/lh/photo/asS7ZL7cDnih6DMq7VmmQg