I'm not sure what the Scottish Parliament can do to influence BAA at LHR - I very much doubt that BAA will play a blind bit of notice to any protestations from Holyrood!
It certainly would appear to be a questionable tactic to reduce to a 4 a day EMB-145 service. Given the vastly increased costs mentioned for operating regional jets into LHR, this is surely likely to lead to a decrease in profitability rather than an increase, although the flex econ pax numbers mentioned earlier might mean BD could get away with charging a kings ransom for the peak time flights!
Presumably doing so would mean the mainline base would close, but the regional one would expand slightly?
To be honest, if domestic routes are losing as much as claimed they might as well just ditch them now and look to feed traffic through FRA etc instead, paricularly when the new runway comes on-line. What is the nature of the STAR requirement for at least 4 daily to LHR - can BD get out of that easily?
Whatever they're doing, they surely need to announce soon if it's to be in place for the spring timetable.