63In its application, by virtue of Part I of this Schedule, to a decision made before 6th December 1968, section 237 of this Act shall have effect as if for subsection (1)(a) there were substituted provisions corresponding to section 170(1)(a) and (b) of the Act of 1962 and as if subsection (5) contained a proviso, corresponding to that in section 170(3) of the Act of 1962.