footster,
We know ASW / T3 have left a gap in the market at PLH. One of the oldest sayings I learnt in business was 'there might be a gap in the market, but is there are market in the gap'?
Of all the airlines I know of with UK passenger ops, there are very few who have a business model based on aircraft small enough to squeeze into PLH. Airlines don't need much notice if there are rich pickings to be made.
Airlines and airports are separate businesses - I don't think they usually work well when both have the same parent - but again, if the airport was a going concern, there has been plenty of time for another operator to express interest.
I'm also sceptical about an operation using twotters, or similar sized aircraft - they are great puddle jumpers, but how can they compete over land which is relatively well traversed by (non-APD paying) road and rail links?