I doubt that Southend will charge anything for handling their own aircraft
Of course Southend will charge for their aircraft . SEN is a distinct and separate entity with its own costs. Stobart Air would need to be paying at least the same amount as easyJet. Any entrants who could potentially enter the airport in the future on the same routes (as hypothetical as that may be) would have to bd offered the same deal as Stobart.
Where on earth did the £20 figure comf from ? Totally arbitrary and pie in the sky, as other contributors have said few retail outlets, not all passengers parking and if easyJet are paying more than £1 - £2 per passenger I'd be surprised.
Serko, what is your source of this £20 figure?