WW would be paying reduced fees as they are based at CWL. Don't forget the operating costs for fuel, landing take-off, handling staff, crew, engineering, catering etc
If you getting lower than required operating proffit then it's better to cut your losses and have the aircraft sit on the ground generating a small loss.
Now if WW moved onto operating some charter flights then you could see more profits coming in similar to what Jet 2 and GSM used to do with their 737's.
There is a reason that the Charter airlines such as TOM, TCX etc are withdrawing out of the traditional spanish destinarions which is £ v Euro. A holiday to spain is not as cheap as it used to be hence Turkey now being added to most tour operators.
We are in a recession and until the airline industry comes out of it and passenger numbers start increasing again there will be a reduced need for flights to the likes of Spain and Portugal.
If WW brought in their 4th aircraft to CWL and not sent it to BHX then we would have had a greater offering of flights in the summer. And not just withdraw services to replace them for new destinations,