This used to be my local haunt some 30-odd years ago when I lived in Notting Hill and I spent many a happy beer and curry filled night (and day) in the locality.
I tried every curry house there at that time, many (and the best) of which no longer exist. The one that we avoided was Khan's. Well apart from the one time we went there. It's offerings were over priced, the setting too formal and the curry, while adequate, was well below the quality of the surrounding smaller eateries. But as I say that was over 30 years ago.
Your description of the curries is spot on from my memories though especially the green Jalfrezi and the smokey Dhansak, both very characteristic of the area's curries.
It could be that they adopted the better styles from the smaller places that went out of business. It may be that you now know why I have very high standards when it comes to BIR. ;D