Hi Bamble,
I have sent you a personal message with the recipe location that Unclefrank was kind enough to speak well of.

FJ

Hi PaulP
The links were just to highlight the puree stage of the recipe which is base sauce as we know it.
I am not suggesting the recipe itself, just pointing to the puree stage (used watered down) as another example of a base sauce.
Purely for interest.

Good things sometimes come by chance!
I normally bulk cook a 1Kg bag of frozen chicken breasts (defrosted first of course).
The cooking liquor that is strained off is so tasty that I use it as a spicy stock in other recipes.
Rather than having to precook chicken in order to get this sauce, I worked on a specially prepared version, replacing the chicken with chicken stock.

Wanting to make a quick curry and having none of my normal base I thought I would use this instead.
So I put together a very simple curry and was amazed at the result, so much so that I felt I had to share it with others.

I initially used a supermarket's own curry powder, but felt it could be improved by a more specific blend.
I have made this with Hot Madras Curry Powder and also Tandoori Masala powder, both by RAJAH and they are both excellent.
The actual curry is very simple but bursting with flavour.

C45 Curry Base Sauce (Makes 400 ml)

3 tbspn oil
100 gm onion (prepared weight)
15 gm ginger (prepared weight)
15 gm garlic (prepared weight)
0.5 tspn salt
1 tspn turmeric
0.5 tspn ground coriander
0.5 tspn medium curry powder
0.5 tspn chilli powder
0.5 tspn ground cumin
0.25 tspn ground cinnamon
1 tbspn tomato puree
200 ml chicken stock (I used an OXO chicken stock cube in 200 ml of hot water)

Preparation
Chop the onion.
Grate the ginger.
Grate the garlic.
Mix the tomato puree with 2 tbspn of hot water.

Cooking
Heat the oil in a wok or heavy pan over a medium heat and cook the onion, ginger, garlic and salt, stirring regularly, for 5 min.
Stir in the turmeric, coriander, curry powder, chilli powder, cumin and cinnamon.
Stir in the diluted tomato puree.
Stir in 200 ml of chicken stock, bring to a boil, reduce the heat and simmer for 15 min, stirring regularly.
Allow to cool and transfer to a measuring jug.
Add sufficient water to make 400 ml.
Blend until smooth.
Store in 200 ml quantities.

House Curry
2 tbspn oil
1 tspn chilli powder
1 tspn RAJAH hot madras curry powder or RAJAH tandoori masala
200 ml C45 Curry Base sauce
2 tspn tomato puree
0.25 tspn salt
1 portion precooked chicken (see notes below)

Preparation
Add 100 ml of water to the C45 curry base sauce to make 300 ml and warm before use.

Cooking
Heat the oil in a pan over a medium heat and cook the chilli powder and spice mix of choice for 45 seconds, stirring constantly.
Add the tomato puree, 40 ml of base sauce (1 chef?s spoon) and salt and cook, stirring regularly, for 1 min.
Increase the heat and add the chicken and 80 ml (2 chef's spoons) of base sauce and cook, stirring regularly, for 3 min, adding base sauce as necessary to maintain the desired sauce consistency.

Serving
Serve with rice and optionally garnish with a little freshly chopped coriander.

Notes
Raw chicken (1 inch cubes) can be used instead of precooked but the cooking time will need to be increased until the chicken is fully cooked.
Additionally, with the longer cooking time, more base sauce or even some water will likely be required to maintain the sauce consistency.

This curry was one of the best I have had and a real surprise (in a good way) 

Not sure whether to make any comment after the unintentional upset I seem to have opened up elsewhere  , but I agree with razor.
I also use Rajah. My local ASDA also has a good supply.
My chilli powder of choice is Rajah 'Extra Hot Chilli Powder'.

Razor,

Your comments about my style is exactly true.

I have never intended to 100% replicate any given curry from any given restaurant, but wanted a whole load of curries that were distinctive and delicious (my opinion of course and that of other curry lovers I have cooked for  ).

So they may not strictly follow true BIR and that's why I called them restaurant style meaning that they may use a traditional slant but are cooked quickly in BIR style ie with base sauce and precooked meat. There never seemed much point to me in cooking loads of curries (50 odd at present) that are all just variations on a theme as your post correctly observed.

As to them being complicated, I feel that they are in fact fairly simple, but well worth any extra effort that may be required.

Maybe this debate will go beyond what I ever expected. ;D

Rest assured no offense has been taken.