I would advise the OP to actually call BA and ask them to re-assign the seats to something more satisfactory. I once had to do this when I was pre-allocated a seat I wasn't at all happy with at T-72 (when I was a Blue). It did, however, require a great deal of persistence and being passed around from one person to another until finally I spoke to someone with the power to do this. Unless things have improved since then, the OP will have to decide if he has the patience for this, or is prepared to gamble on being able to sort things out at T-24 (or failing that, when on the plane).