my wholly non ian sinclair-take: it wasnt that surprising dubstep was from south london, cos south london has always had more of a reggae pedigree (why more than east london or west, i dont really know, its just how its perceived as the carribean capital of london), and yeah, most of those guys were suburban, but giggs and those guys arent (or are they? i dont know peckham well enough, apart from peckhamplex), its just something about the tension in the south london air that sucks your energy out, lol, im not sure how to explain it, though i am prob biased.