I hope you can help. I have searched the forum for information on timing of BA change to Business Class but may have missed this

I am flying with my wife from heathrow to Mumbai next February for our 25th wedding anniversary. One the way out we were booked in First Class on BA0199 but I am now told that they have no first class so I have the option of being downgraded to Business (with a refund) or travel on an earlier (less convenient) plane with First Class.

If I stick with BA0199 (which I am inclined to do) then I have been told that the plane out will be a 777/200. I have also been told by BA that by December 2019 all 777/200's out of Heathrow will be refreshed. However, the lady who told me this did not know what that meant. Does it mean the new configuration? How can I tell? I have provisionally allocated seats 2J and K - is this a good choice?

Whilst writing I am returning in First Class from Delhi on BA 0256 and have seats 2A and 3A. Any views here?

Many thanks

Paul