Tuesday 3 December 2013 7.29pm
Westminster boating base is the other place (or it was a few yrs back - you'll have to check).
Depends which side of SE2 you are.
The RYA website lists all training schools. You need level 2 iirc, to rent dinghies on hols etc., so I'd go for that if you have a chance.
...if you press it, they will come.