The extra IOM/LCY capacity is seriously needed and the extra rotations by BACF are most welcome. It is getting harder to book a seat on this route at short notice.
I do wonder whether FlyBe adding such a substantial number of seats to an airport which is as almost as remote from Central London as Birmingham will help to satisfy any additional London bound traffic demand. FlyBe seem to have done a deal with MAG to open routes from STN as part of their reported 3 year deal at MAN. I guess this is another move under our open skies arrangements. It would have been better to encourage the existing operators to increase capacity and thus secure route continuity. Although sadly it seems easyJet are content to limit capacity in summer to use their aircraft for more lucrative work.
BTW the EuroManx STN route lasted about a month IIRC.