I know there are tons of great Indian restaurants in London, and I'd love to eat at most of them. But I'd especially like to go to restaurants with good southern Indian food (my in-laws are from Mumbai) when we're vacationing in London this fall. I've come up with a couple of restaurants that seem to serve southern Indian food (Bombay Brasserie, Rasa Samudra, Cafe Spice Namaste), but are they any good? Are there any others? I'm looking for both quick lunch places and nicer places for dinner.