Went to Battersea Park today.
Saw dragonflies 8-) Must go to Richmond Park and see if they are out there too.  Dragonflies in Britain don't live very long (see previous link for clues as to how long) so if you want to see them now is a good time.

All in all a wonderful day out.  So good I didn't even resort to listening to the MP3 player I had brought along.