I used to live in Twickenham, Chavender, and, now that you mention it, I've been surprised by the quality of the Indian restaurants round here too. Maybe I just haven't been going to the right ones. SE1 has countless redeeming qualities,but every so often I've sneaked back to visit friends and enjoy Middx Indian food....
I have also regularly enjoyed take away from Mumbai and have eaten in a couple of times too. Lovage is also good, although I have only had takeaway once - their takeaway dishes are different to the restaurant menu - and I agree Cafe Nawaz is worth a visit.
My fave is Cafe Silka in Albion St SE16 been going here since it opened the food is the best I've tasted
Thurs and Sunday you can get a starter,main, side dish, rice and nan £10.99 pp.