I don't believe they even looked at the fare paid for that trip. It was a late aircraft change and I was unfortunate enough to be in one of the rows that did not exist on the replacement aircraft. Those with boarding passes that matched seats on the replacement aircraft remained the same, those that had seats that no longer existed were put elsewhere.

But they did it really badly. I was in the BA lounge for about 5 hours prior to boarding, and they could have paged me to discuss my options. I was traveling home LHR-HKG-BNE and would have been happy to take any other routing on BA, QF, CX to get me to my destination to arrive on the same day. But instead they just waited till I got to the gate and handed me a new BP. Nothing was said until I asked why I now had an economy (WT) seat. No compensation offered at that point, just told I would be given a complaint form to complete on the plane.