The repeal by the 1972 Order of section 13 of the Revaluation (Consequential Provisions) Act (Northern Ireland) 1936 [1936 c.11] or section 19 of the Revaluation (Amendment and Consequential Provisions) Act (Northern Ireland) 1957 [1957 c.5] does not affect any change made under the said section 13 or the effect of any memorandum under subsection (4) of that section.