Perryman, according to the Oxford Dictionaries, a chav is: "[a] young lower-class person typified by brash and loutish behaviour".

So, by definition, a middle or upper class person who exhibits "brash and loutish behaviour" is not a chav. Those people can act like chav, but they cannot be a chav by definition.

This is why the term is arguable elitist. This is why some non-chav Guardian readers get upset by the term [arguably validly so].