I'm led to believe that the BA 767 retirement is pretty much carved in stone for the end of this year unless significant money is spent on upgrading some elements of the avionics.
Of course, we've seen BA grant stays of execution before, so the issues with the 787 engines, the additional ex-Monarch slots, potential for supply issues with engines for the 320neo, may be enough of a perfect storm to make spending the money worthwhile, but don't hold your breath.
We're not talking about delaying the retirement of one or two aircraft from a larger fleet, but running down a whole fleet.