British Airways Tristar callsign in 1980?

Hi all

I am struggling to think of a title for the picture of a BA Tristar which I have just painted. It is in the colours of the old red, white and blue scheme circa late seventies.
I was wondering if anybody remembers what callsign they used. Was it normally Speedbird, Shuttle or something else. It’s a bit of a long shot but if anyone can recall any particular flight numbers flown by them that may also be useful.

Thanks

A