Belfast is identified on the airport website as having the greatest potential after London and it would seem that Eastern would be the best candidate (to BHD, of course). The J41 would be an ideal size, BE's Q400s and FR's 737s would be too big for what would be a fairly thin route.
Having said that, RE might be a possibility although they don't operate into DTV at present. They do operate to BHD however and could do a DTV - ORK link via BHD - just a thought.