I've tried Rajah & East End curry powders and, on their own, are an unsatisfactory spice mix.
I have loads of Asian shops near me and none sell Eastern Star, Triton, or Natco spices.
I think the spice mix, for the finished curry, is very important.
It accounts for a lot of the aroma.
I ruined a curry, the other day, by using a blend with garam masala.
The garam masala was really strong & it dominated the meal.