I was traveling with my wife (Note: in business class/club world) from Seattle to Bangalore via connecting flight in London and we reserved our seats together while booking the tickets. But mysteriously they changed it later and when we got our boarding pass, they assigned 11h and 5d. Called several times but they couldn't do anything and gave us wierd explanations like may be some one else needed those seats and there are no other seats together available. When we boarded, the whole plane was empty and still they didn't allow us to seat together. When we arrived in Bangalore (India), we had to wait 4-5 hours for covid results, looks like this is required only from passengers coming from UK and SA and again they didn't tell use anything related to this. Stay away from BA and avoid UK for connecting flight.