Subject to paragraphs 2 to 5 below, where apart from this paragraph anything done under or for the purposes of any provision which is repealed, amended or substituted by the Act would cease to have effect by virtue of that repeal, amendment or substitution it shall have effect as if it had been done under or for the purposes of the corresponding provision in the 1955 Act or the 1957 Act, as the case may be, as amended by the Act.