JerryM , for the time I have been on this forum I dont think there is any member who has looked in such depth as you to find ' the missing link ' I reckon if you havent found one by now there isn't one

I have been making just Madras and the odd Korma for the last year mostly at weekends , I have stood behind two BIR Chef's and watched them make a Madras , Ive watched no end of video footage and they have all used the same Spices / Process that we all seem to use on the Forum .
Only just lately have I been able to produce better tasting Curries
consistently that my local T/A

Sometimes the T/A Curry is very good and sometimes it's just hot and flavourless , they only have one Chef which I would think would stick to the same Recipes all the time so how can they produce the good and not so good Curries ? Same Chef , Same Spices , Same Recipes .
For me I beleive it's all in the cooking technique , about a Month ago I did my usual Madras Curry and I just had the feeling I had overcooked the Spices the end result was just a hot but flavour less Curry , this is why I beleive our T/A is so inconsistent , being so busy it's easy to miss that ' perfect time ' to add that first ladle of Base Sauce so as not to overcook the Spices. For the last few weeks using the experience I have gained I have made sure the Garlic / Ginger and Spices are fried for a minimum time and are not left at rest in the frying pan where they can burn in seconds , I can now produce a Madras which is consistently better than our T/A . ;D