In the recipe I followed the yoghurt curdled and the dairy flavour in the finished dish wasn't really what I was looking for in a curry. No matter though, the technique itself and the texture of the brisket were fabulous so I'll do it again in future but maybe using one of the recipes from this site.
Heya natterjack
Yoghurt can be tricky to cook with and if you let it boil it will curdle, best to keep it just below boiling point and add at the end of cooking if possible.
I've posted that lamb madras recipe and a pic of the finished dish, give it a whirl if and when you get a chance.
I've had a good look round the forum now and I'm going into information overload I think! A couple of initial observations from the myriad of posts I've read so far would be that I think people over-complicate things unnecessarily and that there seems a huge differential in contributors underlying cooking abilities - which is what causes quite a large difference in peoples cooking results even when based on identical recipes.
I am enjoying reading and browsing the forum posts though.
Cheers and good Karma!