It seems that the relationship between Stobart Air and the airports has become more "arms-length" than it was. I believe that EI own the -600s and lease them to STK, which probably dictates a large part of where they operate to. Stobart allowed flyBe to take over the DUB-SEN route, for reasons which were never clear to me. Its strange that they have never resumed the route - unless the aircraft can gain better returns elsewhere.