Wizz Air / LCC operations
Not sure what business plan Wizz operate, but if it's like Ryanair's Low Cost operations, wanting everything free from the airport, then maybe Newcastle airport would rather have airlines who are willing to pay fees & charges, as revenue from retail & catering is not fantastic on budget airline flights. Newcastle have been careful to maintain about 1/3rd Business + 1/3rd Leisure (TM/TCX etc) & 1/3rd LCC. They won't want to lose fee paying airlines to ultra low cost carriers who don't pay charges. - Airport needs to make money.
Again I'm not sure if Wizz is a FR style Ultra low cost carrier, but if so, could be a reason it is not being encouraged.