5. In a case where on 1st April 1981 a certifying officer or public service vehicle examiner has started, but not finished, any action under the powers conferred by section 128(3) of the 1960 Act, the repeal of that subsection and the commencement of section 16(1) are, for the purposes of that action, deemed not to have occurred, and in a case where on that date proceedings have been started, but not finished, in respect of the offence specified in the said section 128(3), the substitution specified in paragraph 1(4) of Part I of Schedule 5 to the 1980 Act is deemed not to have occurred.