Skipness One Echo,
There are about 25 BA pilots (mostly captains) on secondment to BA Connect. They are currently flying the RJ100 out of EDI and BHX. The new subsidiary which BA is setting up will be a LCY operation with all the RJ100 flight-deck crews based in EDI.
Over the coming weeks, BA and BALPA will be discussing the options available for these BA mainline secondees.
The answer to your question could be: LHR, LGW and EDI.