LHR Slots
It is fair to say LHR is full and any new entrant must obtain slots from a current carrier
BA has no slot shortage, recent new routes domestic , shorthaul, mid haul and longhaul PLUS currently lease slots toother airlines
BA do need to wait for their new aircraft to switch some of their less profitable slots eg DUB to other routes, probably Longhaul .
No commercial sense in buying more slots in current climate when they already have a surplus