What food is called Lamb Biryani, but is a rice pilaf served with a lamb and vegetable curry?!

What food is called Lamb Biryani, but is a rice pilaf served with a lamb and vegetable curry?

We used to live in Brechin, Angus, Scotland and we used to go to an Indian restaurant in Montrose, Scotland and order Lamb Biryani. It was a rice pilaf served with a lamb and vegetable currry that came in a separate dish and then we put it over our rice pilaf. It was very juicy and delicious and sometimes there were different vegetables in the curry, but it was all great. Then we moved to the US and when we went to Indian restaurants over here, the Lamb Biryani here is just a rice and meat dish that is quite dry and has no other sauce with it. Does anyone have any idea what we were really being served in the Montrose restaurant? I have checked all sorts Indian recipes and none of them even come close. Anyone have any ideas?

I have found "indian" food fairly fairly regionalised throughout the world. I think it is partly the regionality of the restaurants and also local tastes.
British tastes seem to pefer having some sort of sauce with their food (hence the monsterous dish Chicken Tikka Masalla) so Biryani's are served with a side dish. In Glasgow the restaurants serve it with a simple basic curry sauce with no meat or veg, whilst over on the East (from Inverness to Edinburgh) they prefer a small side of simple Vegetable Curry. Whether this has anything to do with the fact that Glasgow "Indian" Restaurants tend to describe themselves as Punjabi/Pakistani and their Edinburgh counterparts as Bagladeshi I am unsure.
I know back in the late 80's Indian cuisine in South East America was well behind Glasgow/West Scotland and even Canada at the end of the 90's had a fair bit to go, but from hearing folks talk here I would be quite happy to think that what you are being served IS a Biryani, but without a side dish of some sauce.