Julie,
S0 great to hear about your first booking with B & K. You're in GREAT hands! I wouldn't consider booking anywhere else.
Yes, I've been to both Mumbai or Cochin. Both are incredible. Read my diary from the 2005 world cruise as I discussed both with photos. My husband (Tom) also worked in Mumbai (Bombay at the time) for 5 months in the 90's so he's very familiar with the city.
In a nutshell, while in Mumbai I went with a friend to the Taj Mahal (Tom had been there before) for the night while Tom stayed in Mumbai and spent the day with a private driver with Lars, Steph and Capt. Dag (they bought some rugs for the ship, some jewelry, had lunch and beers). In Cochin, we went with Capt. Dag on a chartered river boat touring the backwood rivers. It was amazing seeing how the locals live and fish. After cruising the rivers for a couple of hours we went to a beautiful large hotel where there was a W.C. function including an outdoor lunch and dancers (there is a photo of me on an elephant that was taken at this hotel). I have wonderful memories of both of these ports as I'm sure you will! EVERYONE should visit India at least once, it is like no where else in the world.