Flybe would seem to have been the prime candidate to operate domestic services from SEN (who else is there?), but their move into LCY would seem to taken out many of the obvious destinations - either operating themselves or Stobart in BE cls.
Maybe Buster will be right?
The model of being an alternative destination for those cities (both domestic and continental) who don't have a London service looked like a good one, but other than Stobart where are the airlines to operate such routes?