When I say not BIR I watched one of my Indian work buddies cooking a lamb curry for about 8 of us.
He marinaded pieces of lamb with yoghurt, garlic paste, ginger paste, green chili puree and some "meat masala" - can't remember the make but could be Laziza or MDH.
The meat masala tasted like quite a good fiery curry powder. This was marinaded for 24 hours. At cooking time he fried some onions, then garlic and ginger pastes and some more green chili puree. He added some dried red chilis then the lamb (with marinade) then some water and salt. Some more meat masala went in and he had another box of spice which tasted like garam masala to me. He added a bit of cornflour to thicken and it cooked for about 1.5 hours.
The end result was quite pleasant but nowhere near a BIR curry.
I think some of these boxes of spice have their place though and might make a replacement for the curry powder component of our own masala mixes.