I have been booked on an MU flight in the business cabin by Virgin Atlantic following their cancellation of the LHR-PVG route. I have not been able to select a seat nor use the MU website to do so. Virgin's booking reference number and e-ticket info are not accepted on the website. The MU office in London has closed, so I can only hope that when I turn up at LHR in March 2025 to check-in that I do have a seat on the flight, and that their in-flight service is better than their online/telephone presence.