For cookbooks, I think Pat Chapman's books provide a good insight into the differences between UK restaurant dishes and what those dishes might have derived from. That said, a friend who has spent time living in India insists upon going to an Anglo-Indian with me when he comes to visit as he cannot get the 'good stuff' in India. Like the Chinese already mentioned, I accept that Anglo-Indian is just a variant on regional Indian and accept the dishes as to whether i like them or not. I worry less about authenticity because they aren't, that doesn't make them bad.

Oh, and in Edinburgh - not a well known haunt for Indian food - the Cavalry Club is still in front but we have a Michelin aspirational restaurant opened up that I need to try!