Actually the other flight was later so it would not be a noshow... and in the record it of course said "ready to checkin" and there was a countdown. I checked in at 0:00. Or at least tried to. Also the mobile app continued to show my old flight and seats / aircraft for hours after the ticket was reissued, even with a force shutdown and refresh. They definitely have some legendary IT issues and I hope the whole system doesn't come tumbling down one day. I fly a number of airlines and BA's systems seem to be the most challenged.