I made this again last night and thought I'd give some more feedback

Now, if I'm honest, the first time I did that I didn't quite follow the recipe :

When I tasted it, it didn't seem quite right, so I made two small changes :
1) Added a good teaspoon (so...two) of tomato puree
2) Added a half teaspoon of sugar.
This was after tasting it and thinking it wasn't quite there.
So anyway, the one last night I followed the recipe to the letter and it wasn't quite as good. I think it missed the tom puree and extra sweetness.
This could be for a few of reasons
1) My base isn't quite as tasty as Razors
2) My tomotoes aren't very good
3) My local BIR do it with tom puree and sugar

Anyway, thought I'd just mention it! So if towards the end of cooking you think it could do with an extra lift, give this a try.
I also want to say to Razor: the touch I really love in this dish is the garam masala at the end. That's a stroke of genious! It just gives this light, almost lemony lift to the dish. Brilliant! ;D
(for reference, I'm using East End garam masala, which is very fresh, fragrant and almost zesty)