Jetstream start-ups in the UK don't have a great record - when was the last successful one? Can't see why Stobart would take the risk (and don't Firnas have a J31?).
I had assumed that the Dublin link would be linked into the Aer Lingus franchise to allow interlining, if so presumably they would have an interest in what was being operated in their name also.
Also, doesn't this route have the regional fund subsidy - isn't that linked to a named airline?