DEP A350, what are the chances of that happening ....
Next seat/type bid window isn't currently open, will be in July (for one month) - that's when there might be the first signs of internal bids for the type being available.
In service dates vary dependent on source, but
AFAIK first A350 to BA isn't due until late '17 at very the earliest.
Traditionally and for practical reasons the early courses on a new type are populated by existing trainers from within BA (both P1 and P2).