RE: the "25 777s" is this the balance of yet-to-be-refitted 777-200s?
That's the Gatwick fleet (GE & RR powered) and the RR powered 777-200ERs (which were also reported to be reconfigured to 3-class throughout?). There's 28 aircraft according to BA Source with the Rockwell Collins IFE and old seats still.
http://www.thebasource.com/boeing777-200er.html
Essentially assume the following...
All LGW flights
All 3-class 777-200 flights from LHR (BKK, EZE, NAS, GCM, BLR etc.)
Looks like the 777-300ERs will escape with 9-abreast (for now).