I went into MMB to change some seats and discovered our seats on one sector of our trip had been changed to economy.

The flight is from Sydney with a stop over in London before flying onto Helsinki. The ticket is in Business class but now all of a sudden on the Finnair operated flight ( the A350 flight that I specifically booked for) from London to Helsinki our flight is showing as economy.

It says there has been a flight time change. However I can see no evidence of this. A basic dummy booking shows there has been no flight time or aircraft change.

BA call centre is not open today locally.

Interested in any reasons this would happen? The flight is not for three months.