9Subject to the provisions of paragraph 13 of this Schedule, a site licence shall not he 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 permission under Part III of the Act of 1947 has, if required, been granted) if that use is for the accommodation of a person or persons employed in connection with the said operations.