North Flying don't have a reservation system so whilst Citywing can't stop them flying, someone is needed to sell tickets.
They don't have travel agents in Wales?
I think you've missed the point runway30 ...
The route doesn't belong to either North Flying nor Citywing, the route belongs to Van Air who appointed Citywing as a mere ticket seller and, just recently, Van Air have been sub-chartering North Flying to operate the route upon behalf of Van Air.
Van Air haven't folded, haven't called in a liquidator, and being banned from UK airspace if they can't afford to continue sub-chartering other operator(s) to operate the route upon their behalf then they, Van Air, are the ones that should be making any announcement, and talking to WAG, not Citywing who are a mere ticket seller.
I wonder how the WAG subsidy works, if Van Air have been paid in advance, I know that if I were WAG I would be studying any contract fine print regarding breach of contract or whatever.