Under this section where it appears to a council that there has been a material change of use of land, or planning permission has been granted for development and the carrying out of development would involve a material change of use of such land, and the development to which the permission relates has been commenced, it may revoke the related hazardous substances consent. A council may revoke the consent if it relates to only one substance or, if it relates to more than one substance it may revoke it or revoke so far as it relates to a specified substance.