I wouldn't be to disheartened Pete,I've been making Curries for many years, but as a serious BIR curry maker for just under two! ;D
I'm incredibly happy ;D

with my own personal progress & feel confident it will improve.
I've got the Base colour right (Thanks to my local BIR giving some helpfull info) they have more than likely left out their Chefs Spice mix.
Question : Is this the only missing component,not Curry powder,what is their definition of Curry powder is it just a blend of particular Spices which make the Curries a little more individual to various BIR's across the country ? This could be why we are all struggling to get it 100% right, i would seem to be a very logical conclusion.
This brings up another good question the next time we are in our local "could you recommend a Spice mixture i could use to make my home-made Curries taste better"? ;D