Monday 8 July 2013 11.59am
2 places spring to mind near me - Imbibe
on Blackfriars Road
, and Tamesis Dock
on Albert Embankment http://www.tdock.co.uk/
Both have outdoor spaces which is what I'm guessing you are looking for! If not, try Isabella Street
on Saturdays - as the places there are pretty quiet then and need the business!