Two points:

1. Baggage claim isn't always that efficient. I recently flew there in December and my bags (with my Silver tags attached) came out 30-40 minutes later. I've heard of similar experiences. Depending on air traffic (there was an LH, KQ, and an AI arrival at the same time) you may be delayed a little with baggage and overall arrival.

2. The Terraces lounge will be closed indefinitely, according with the ground staff and BA office staff I have talked to. This is because Mumbai International Airport Limited has requested the lounge be closed so that they can proceed with modernization and expansion plans. Inevitably the Clipper lounge should serve as the default lounge for a while.

Kudos to the excellent BOM Guide! ^