More economic illiteracy from FRatSTN:
I would have thought though that Stansted would be the most likely option since there is virtually nill (sic) presence of domestic services now other than Belfast, Edinburgh and Glasgow.
Stansted is in the middle of the countryside. People don't live there in large numbers. Connections are worse than at LHR, LGW and LTN, and that's the reason why domestics - which have continued from other London-area airports - have failed at Stansted.
The only reason that BEE have to select Stansted is that there is no competition. And that means no-one else has made a go of these routes from rural Essex.
Actually, I don't think BEE will base at Luton either. They will probably reposition themselves as a regional airline, connecting the UK's regions, which they do well. Their largest bases are SOU and EXT, both of which are classic regional centres. The best LTN can hope for is a Waterford link - the traffic is there - but that alone wouldn't justify opening a base.