Whatever the reasons, it's getting harder and harder to find a decent BIR curry these days - old school or otherwise.
For the last 15 years or so, whenever I visited relatives in London, I used to salivate at the thought of hitting the Tandoori Garden in Lillie Road, Fulham. The chef there made absolutely an absolutely sublime, to die for Madras and vindaloo (the best I've had in the south, in fact), and the rest of the dishes on the menu were great, too. Tarka dhal nice and thick and garlicky - none of your watery soup-like rubbish. Really smokey, flavoursome saag bhaji, superb tandoori chicken, etc, etc. The man had the touch, and it was heaven.
But the last time I went it had all changed. The chef had left, the decor modernised - and the food ruined. It was bloody awful, in fact.
I wish I could find out where he moved to, as I'm now running out of places to find good quality curries.
One thing is for sure, and that is a really good BIR chef is gold dust.