The relevant bits in the Competition Remedy for BA/bmi state:
The number of slots to be made available would enable prospective entrant(s) to operate up to a total of seven frequencies per day on the Identified UK City Pairs and up to a total of five frequencies per day on any Identified City Pair.
Where a prospective entrant would have operated on one or more Identified City Pairs with the released slots for at least two consecutive IATA seasons, it would be entitled to apply for any slots still available in the quota for the Identified City Pairs to operate frequencies on any European short-haul city pair provided that it also continues to operate the frequencies it is operating on the Identified City Pairs.
So there are 12 sets of Heathrow remedy slots. If you fly the Edinburgh and Aberdeen routes then you can apply for any remaining remedy slots unused to operate them on any European route of your choice. That's where the Newquay slots are coming from. They cannot move slots from Edinburgh or Aberdeen (under separate provisions) until March 2020.
I'd be waiting for a sale of Gatwick slots to be announced.