2(1)Where a group of contiguous or adjacent buildings used as parts of a single undertaking includes industrial buildings used for purposes falling within two or more of the classes specified in paragraphs 3 to 9 of Part II, the particular classes in question may, in relation to that group of buildings, be treated as a single class for the purposes of this Schedule if the area occupied in the group by general or special industrial buildings is not substantially increased by reason of being so treated.N.I.
(2)A use which is ordinarily incidental to and included in any use specified in Part II is not excluded from that use as an incident thereto merely because it is also specified in that Part as a separate use.