I flew on the last LHR-SEA flight on March 31, 1995 (could be 1994, my memory is not so good anymore:-)

I was booked on the flight for March 30, but took a very convenient bump and collected $800 and an extra 24 hours in London. I was offered a bump on march 31, but then they told that I would have to go via IAD as there were no more LHR-SEA flights - so I took what I had.

David