For the purposes of Class A—
(a)the erection of any additional building within the curtilage of another building (whether by virtue of Class A or otherwise) and used in connection with it is to be treated as the extension of that building, and the additional building is not to be treated as an original building;
(b)where two or more original buildings are within the same curtilage and are used for the same undertaking, they are to be treated as a single original building in making any measurement;
(c)“employee facilities” means social, care or recreational facilities provided for employees of the undertaking, including creche facilities provided for the children of such employees.