Try putting .....
www.caa.co.uk/ginfo
into your web browser.
Enter the aircraft registration for the CAA registration details.
Click on" Full Registration History" for the original registration details.
Also
http://aviation-safety.net/database/record.php?id=19461118-0
which describes the accident in which it was destroyed on 18 NOV 1946.
Also mentioned here ...
http://en.wikipedia.org/wiki/BOAC_Flight_777
Malcolm.