Had the Udipi thali and pretty happy with it.
I really liked the lemon pickle that came with the papaddam - very zesty, a sharp vein of bitter acidity, a brilliant acerbic counterpoint to the gushy sweetness of the mango and tamarind chutneys.
Notable among the items in the thali were a spiced potato with lentil, nicely dry and textured, the nubs of lentils against the soft potato cubes, coriander and mustard seeds being a bit more prominent to me.
I also liked the vegetables simmered in coconut milk and cream, along with the toasty flavour of coconut shreds in the nackground.
Other items included courgettes, savoury with onion and other spices; raita - yogurt with diced cucumber; and the southern indian standards of rasam and sambhar - tangy in their own ways.
The poori was very good - very light and fragile, nearly crumbling on touch and somewhat wheaty in flavour.
Dessert was a sour cream of wheat flavoured with saffron and cardamom, washed down with a decent masala chai.
There's a branch in Central London near Goodge street, but the waitstaff there say that the Hammersmith branch is better.