I, too, liked the TriStar but have negative memories as well as good ones.
For example, I remember the time when Caledonian stepped in for collapsed Canadian company Nationair (have I got the spelling right?) in summer, 1993. We should have flown Glasgow-Toronto nonstop but had to make an unscheduled stop at Mirabel for fuel.
Hardly the fault of a model not designed for such long distances, I know, but on the return journey the air conditioning wasn't functioning properly and we roasted all the way from Toronto to Manchester and on to Gatwick.
On a more positive note, I recall the time Leisure International Airways sent out an empty Air Atlanta TriStar to collect myself and other passengers on an unoperational A320. I remember being surprised that we were told we could sit wherever we liked. There were acres of free space!
To come back to BA operations, I seem to remember TriStars being used to Far East destinations such as Hong Kong and Bangkok in the late '80s. Can anyone confirm this?