Second good recommendation (after Yalla Yalla) that I've gleaned from the FT Weekend this summer.
There was an article about samosas (see link below) and Pooja Sweets was recommended.
I tried both their small samosas (4 for £1) and what they call Punjabi samosas (50p each) and enjoyed both at home heated up in the oven and served with some of their yoghurt chutney as well as some tamarind sauce from my fridge. Will be making some chaat with remaining samosas. Both the pastry casing (denser and crumblier for the Punjabi and thinner and crisper for the small) and the filling are well prepared and tasty. Lots of other items (both sweet and savoury) to choose from, link to website below.
Hadn't been down to Tooting for a while so had a wander around. Kastoori is still going and there's a Mauritian place called Cafe Dodo (I think) which looks interesting enough. Still a good area to stock up on subcontinental and Asian produce for decent prices, I bought a variety of things including mangoes, grapes and green papayas.