In its application, by virtue of Part I of this Schedule, to a decision made before 8th December 1969, section 226 of this Act shall have effect as if for subsection (1)(a) there were substituted provisions corresponding to paragraph 1(a) or (b) of Schedule 4 to the Act of 1945 and as if subsection (5) contained a proviso corresponding to paragraph 2(2) of Schedule 5 to the Act of 1947.