When I went to Mumbai, I went YYC-LHR on AC, and then LHR - BOM on Jet. As the boarding pass out of LHR was a AC one, I got to use the AC Lounge in London with no problems.

The only time you really miss the lounge is when you are leaving Mumbai Airport. *G doesn't get you into any lounges, but having a Master Card does. (Any Master Card).

The "Y" service on Jet Airways is quite good. I wouldn't hesitate to make the exact same run again using 9W.

David