Those are the usual routes that get the nod - BE charge much higher fares than these airlines do.
BE started operating the routes at NWI with Astraeus 737's and lead in fares at £39 IIRC. As INKJET says, I think they will find that the lure of STN will put a stop to any serious success - it's simply too close to be able to justify the higher costs ex NWI.