I really wish I knew, George. As I said (probably in another thread), the new T/A in Bodmin, Ganesha, does a superb Madras which I would love to be able to emulate. It, too, is lightly spiced, but it is without doubt different to the curry that I cooked tonight. The only way in which I will get closer is to have both in the house at the same time, ideally both cooked at about the same time before I sample then, and then try to work with my wife (who is good at identifying flavours) what is missing in mine that is in Ganesha's, or what is in mine that is not in Ganesha's.
** Phil.