Barretts suggest where to live in Balham

Where are Balham's boundaries? Does it go as far as Tooting Bec Tube Station or Ritherdon Road? Where does Clapham South start? I noticed that there are some SW12 postcodes up by Wandsworth Common. Can Balham claim any part of Wandsworth Common? And isn't Bellevue Road realling Tooting?

Bet that's stoked some fires! But I'd be interested to see what others think too.