flyer55,
although i don't think it's going to happen........ your point about LGW being mixed fleet is irrelevant. Only the cabin crew are mixed fleet.
The airbus' are replacing the B737's, and that's it. BA could run them all, GB could run them all in conjunction with BA........ doesn't matter, and the cabin crew would still operate a mixed fleet rosta.
The 777's are all crewed from LHR, albeit with some having a preferred LGW report (please someone at BA correct me if thats not the case anymore, but it certainly was)
I believe GB have 1 a/c in MAN during the winter and 2 during the summer. Although a previous post suggests MAN is closing, so that'll mean no a/c up there presumably!
bpm