Hi Howard Long,
You’re not late to the game. There are only 3 GE-powered 772s at LHR with the new IFE - G-VIIW/X and Y. These were LGW aircraft pre-covid that used to operate the LGW services with F. When that cabin was no longer offered at LGW, they were moved to LHR. They were then fitted with Club Suites, had the IFE upgrade and had their configuration changed to match the other GE-772s at LHR. As for aircraft assignments, there is no differentiation between these 3 oddballs and the rest of the fleet so it’s pot luck whether you get a slightly better IFE experience.
Cheers,
Champ