5(1)In this Schedule “at a material date” means at either—S
(a)1st July 1948, or
(b)the date by reference to which this Schedule falls to be applied in the particular case in question.
(2)Sub-paragraph (1)(b) shall not apply in relation to any buildings, works or use of land in respect of which, whether before or after the date mentioned in that sub-paragraph, an enforcement notice served before that date has become or becomes effective.