Don't write them all off yet, there's still phase two of the summer schedule to be released; I would expect Dusseldorf to be a part of that although I have no inside knowledge... But from the schedule data, there looks to still be a DUS based aircraft (operates to MAN midday) but no flights in the morning or evening for that aircraft when it would usually fly to BHX and extra rotation to MAN. Unless there will be a new destination for DUS (probably unlikely given all the cuts there) then it would make sense that BHX will still be served.