I'm not promoting and have nothing to do with this school but would like to mention Bertrum House on Rowfant Road and Balham High Road. Its for kids from 2 & a half to 7 so covers quite a few years.
Its particularly good for parents who have just moved to the area and have no other private place secured or have been let down by state offers made in April.
They usually still have places for September 2014 especially for the 4 year olds in reception class and I cant recommend it enough having had neighbours children and my own go through various stages, small classes and going onto top schools age 7+
Do give it a thought if you need last minute as its filling up fast :-)