Wonder if anyone can shed some light on a problem a friend is having. He bought a Plus fare LHR-MAD a few months ago, flying today. He tried to move to an earlier flight and he is only being offered to do so if he pays hundreds of pounds. There are loads of empty seats on most flights. BA call centre have been completely unhelpful and just tell him he cannot do so without properly explaining what the issue is.

The only theory I can come up with is that he happens to have booked BA518 which is operated by Iberia, and for some reason hidden in the small print, maybe IB-operated flights are not eligible for same-day change despite being sold as an identical option to a BA-operated flight. If that is the case, I think it's pretty sharp practice.