I think Michaels theory is correct; people are in this climate less willing to fork out on private schools particularly for younger children. There was a report somewhere on falling rolls in the local Dulwich prep schools etc. Lewisham primary schools, particularly around FH have really good reputations so its senseless for anyone to even consider a private education unless they are really minted. Southwark has more of a mixed bag from what I can gather however the ones around East Dulwich are meant to be very good.

To answer your question, as far as I know from friends their experience with Lewisham has been very good and few seem disappointed with what they have been given. Perhaps Lewisham is just better at forecasting and planning than Southwark.