fligŵhtrider - if an airline applies for the remedial slots and meets the required terms set for qualification and necessary financial standards for their release then BA are obligised to comply.
Other routes covered by remedial slot releases include Boston and Miami , plus former bmi routes to Cairo, Riyadh, Nice, Edinburgh, Aberdeen and Moscow.
Virgin used and returned some for their Aberdeen and Edinburgh “little red venture” but shuttered that offer due to remarkably dire performance and returns - the only winner being IAG fellow carrier Aer Lingus me thinks ! Manchester wasn’t a remedial slot route however Virgin were required to use ALL of their own slots to meet the qualifying requirements set for the award of the remedial slot allocation.
Flybe are now trying those same routes with remedial slots and qualifying as a new entrant.
Delta use a remedial slot award for their Boston flights whilst Miami was also tried and returned whilst they now use their UK arm and slots for that route today.
So there remains a number of BA slots that can be demanded under the remedy slots systems to qualifying carriers if any want to try their luck.
By the way Heathrow isn’t necessarily a guaranteed gold mine and BA retain many of the jokers in the pack because they can determine what slot times and pairs they provide from their very extensive pack - more than 50 % of all available slots at slot constrained Heathrow today.