Amaya is clearly not Indian food as the average Indian knows it. The food, which is prepared with care and elegantly presented does not resemble anything that I ate during my months in India, although the flavors do delight. Almost all of the dishes are quite small, meant to be shared amongst the diners at a table. The food is largely influenced by Northern Indian cuisine, with an emphasis on the tandoor (clay pot oven), but there are also kebabs and plenty of veg dishes to be had as well.
If you want a bit more heft for your quid, I would recommend getting a biryani, which is a rice dish and is the most generously portioned dish that we had in my group. There is also a quite satisfactory wine list, with many choices by the glass. I did encounter a bit of trouble with this, however, when I ordered a Muscadet by the glass. The bottle was brought over to the table, but was mostly empty. As my group was the first of the day, I inquired when the bottle had been open. I was assured that it had been opened that morning, but when I asked who they served the wine to this morning, considering I was one of the very first customers, I never quite got an answer. Still, he was willing to open a fresh bottle for me, which I requested. In the end, the wine was quite good, but you do need to be careful with wines by the glass that they haven't been left over from the night before.
This being Belgravia, obviously the meal didn't come cheap. Still, it is an elegant setting for a classy meal if you can pay the price. Just don't expect to find food like this in the stalls on Nariman Point.