Mark - Many thanks for obtaining and reporting your restaurant owner's comments - invaluable in building up a picture. But one thing concerns me - he said any curry powder would be 'fine'. These people never like to offend. I'm sure Rajah curry powder would be fine. But would it be optimal or best? There's likely to be a significant difference, including the ingredients which lead to the best taste, between a curry powder mix which is fine, and one which is optimal. In my mind, I think the inclusion or omission of things like green peppers and chicken stock could be the difference between one local BIR and another, fine tuning. BIR curries do vary a bit. But I also believe the common 'special taste' is from what's in the curry powder, or perhaps herbs.