LHR
I have absolutely no inside knowledge about what BA or BMI may, or may be not, thinking nor do I profess to understand the charging structures of the BAA to airlines at LHR.
It would, however, be interesting to know if both (LHR-NCL & LHR MME)domestic routes really do produce valuable onward traffic or whether by discounting the domestic connecting sectors (sometimes they are for free on longhaul flights) for onward/inward bookings they are taking away, or making substantial holes, in the overall profitability of the whole round trip.
I'm sure that both airlines have extremely sophisticated revenue mapping systems and know exactly what the returns are on each sector flown; so my advice is to ignore all the press hype and wait for real information from the two carriers concerned. Summer holiday time is often a 'slow news' period and our local rags and TV jump on anything to fill their copy or airtime.
GH