The first six Tristars were the definitive BEA order (a prototype came over to the UK with large BEA decals on it prior to the full BA merger), later ones went to BA mediumhaul routes (eg Gulf) for which they were more appropriate.
Eleven (11) of the first twelve (12) TriStars (s/n 1002 - 1012) were delivered to Eastern Airlines, the twelfth s/n 1001, was always painted in "Lockheed house colors".
The L-1011 with the big BEA decal, that made the Farnborough trip in 1972, was s/n 1006. A flight test airframe that was later delivered to Eastern as N305EA. Later it was bought by Delta and operated as N782DL.
The first BA L-1011 (from the BAE order) was s/n 1083 G-BBAE. The first BA L-1011-500 was s/n 1157 G-BFCA, currently ZD948.