I got round to finally trying this base last night, it looks the part and has a very subtle undertone of Indian/curry flavour, i think this is going to be an excellent building block for a final curry.
I was initially concerned about the 3 litres of water to 8 onion ratio as it produces a very runny base, i cooked the final base for an hour to thicken it up.
I can not get Rajah Madras Powder so substituted with Hot Curry Powder, i also left out Coconut Block, Tamarind & All Purpose Seasoning.
Will be trying a curry tonight.
The biggest thing i learned from this process is the making of a paste and then frying it to release the proper flavour, from now on i will be making a paste everytime i cook a curry and frying it off in the initial oil to fully release the flavour....Stew