What we (who presumably have either never been to, or at least never spent very long in India) call 'authentic' is neither here nor there. What's our experience ? Bangladeshi-run curry houses and a couple of programs on telly ? At the Indian YMCA it's cooked by, served by and served to Indians. I think they know their own shit. So for 'authentic' I don't think we need to continue a discussion because no-one really has anything to go by do they. Whether you like the food or not is a separate question. This is London and there's plenty options if you want another option, as has been already pointed out.