BA was the only airline i have flown on that does not supply baby food. Emirates bring out a tray of it for you to select from.

At 15 months I assume she is on solids. I cant remember if BA gave us a child meal for my kids, but i suspect not given they don't have a seat.

As I recall they gave us bits to make up a meal. It never occurred to me traveling business that we bring our own child meal - so I would suggest in the absence of anyone positively telling you that they will get something to take your own.