Retrospective effect of customs notification deemed to commence earlier, applying an amendment to customs and tariff law. A government notification amending a prior customs notification, issued under the powers of section 25(1) of the Customs Act and section 3(12) of the Customs Tariff Act, is declared deemed to have, and always to have, for all purposes, come into force on an earlier specified date, thereby giving the 2018 amendment retrospective effect and fixing its operative commencement to that earlier date for all legal and administrative purposes.