Subject to paragraph 13, a site licence shall not be required for the use as a caravan site of land which forms part of, or adjoins, land on which building or engineering operations are being carried out (being operations for the carrying out of which permissionF1 under F2the Planning Act has, if required, been granted) if that use is for the accommodation of a person or persons employed in the course of those operations or the person or persons who own any estate in the land on which those operations are being carried out.