OK, I chatted to the guy again tonight and have his recipe for making up his standard sized pot of base sauce, bear in mind the size of the pot is huge, its about 14-16 inches in height and diameter. The guy is very honest and is entertained at what I am doing, he has also said he would be happy for me to come and watch him make the base.
This is a full recipe of base sauce in the quantity that a BIR would make, when I refer to chefs spoons below I am referring to the big spoon they use to make all the curries, I estimate this is approx 2 table spoons, all measurements are round spoons, not level nor heaped.
In this 14-16" pan add veg oil up to a depth of 3/4 inch, heat on a high heat
Add 2 chefs spoons each of ginger and garlic puree, he was at great pains to point out to me this should be cooked until brown as Pete has seen before and to make sure I keep stirring it.
When brown add 1.5 chefs spoons each of curry powder and turmeric, add half a level chefs spoon of chilli powder (I have seen him add chilli powder to my dishes and he doesn't use very hot chilli powder)
Stir quickly frying for a short while and then add some water "otherwise it gets too sticky/thick"
Next add the following chopped:
30-35 onions (thats no typo!)
5/6 carrots "or 4 big ones"
3 green peppers
half a bunch of celery
and half a cooks spoon of salt
2 desert spoons of garam masala "be careful not to over do this as it will easily dominate the base if you add too much", this is equivalent to 4 level TSP
fresh coriander and tomato paste*
Add water and see the top post now for how long to cook this for and what to do next
* I didn't get the measurements for these 2 ingredients, will do next time I go
He was at great pains to be wary of adding too much chilli, salt and garam masala. Too much of any of these will ruin the base and are irreversible.