Vile airport. Just did this a couple of weeks ago from a domestic Kingfisher flight (BA codeshare) from Hyderabad to the lunchtime BA198. Had about three and a half hours for the transfer which took about ninety minutes from landing at domestic to sitting in the BA lounge in the international terminal. I used the transfer bus in the end rather than booking a car for the connection. The bags were tagged all the way through and I didn't see them until London.