I suspect the restaurants use nothing more than the following to make virtually every curry:
Curry powder (I use the restaurant masala from the curry house cookery in the ebook section)
Chilli powder
Salt
Sugar
Lemons (whole or juice)
Garlic paste
Ginger paste
Pasata
Fresh coriander
Fenugreek leaves (dried)
Ground almonds
Creamed coconut
Single cream
food colourings