Hi
Came across this site by googling and looks quite interesting
http://menuinprogress.com/2008/01/indian-takeaway-curry-base-sauce.html
QuoteAfter a lot of trial and error, we came up with the technique of starting with a "ubiquitous base sauce"
No you didn't! You fell on a forum like this one or one of the ubiquitous curry secret books now available and went from there. A bit of honesty wouldn't kill them would it? ::)
That site is about 10 years old, i have cooked a couple of dishes from their many moons a go, Dhansak is very nice though.