Much has been written on the fact BA were the launch customer for 777 GE engined aircraft and the fact that they later took 777s with Rolls Royce Trents. This was because thay had cancelled a 744 order with RB211s and to forfill the contract with RR they took the last ones with the Trents.
So they now have a 777 fleet with mixed engines. They are probably the only 777 operators with more than one type of engine.
BA are traditionally a Rolls Royce customer. What made them go for the GE engine in the first place?
If there are subsequent 777 purchases will they be GE or RR powered?
Do BA have a preference and are there any advantages to either of performance/reliability etc? A would know better than anyone the merits of either.