<<Disclaimer: Verify this information before applying it to your situation.>>
This may apply to BA and others. I learnt the hard way on a KLM flight. The
flight I was due to fly on, for which gf meals had been ordered and
confirmed, was unable to fly at the last moment because of engine trouble.
We had to wait a few hours for another plane to arrive. The gf meal order
was not transferred. This left me without food from Amsterdam to Kuala
Lumpur. Amazingly they had no fruit on board.
Obviously we missed the connecting flight at Kuala Lumpar so when checking
in for the next leg I asked about the gf meals. I wasn't surprised to find
it hadn't transferred for that leg either. This was with Malaysian Airlines
and they were very helpful and managed to provide excellent gf meals at
short notice.
Now I confirm gf at every check in.
Margaret