7Nothing in this Act shall affect the operation of section 79 of the [1955 c. 16 (4 & 5 Eliz. 2).] Food and Drugs Act 1955 (special provisions as to the compensation payable under a local Act where the use of a slaughterhouse is rendered unlawful by the provision of a public slaughterhouse) in relation to any slaughterhouse the use of which was rendered unlawful before 1st January 1974 (the date on which section 5(3) of the [1972 c. 62.] Agriculture (Miscellaneous Provisions) Act 1972 came into force).