84As from the appointed day, article 7 of the [S.I. 1965/1536.] Visiting Forces and International Headquarters (Application of Law) Order 1965 (which empowers the making, by agreement, of exceptions from, among other things, the exclusive privilege of the Post Office with respect to telecommunication) shall have effect as if for the words " section 24(1) of the Post Office Act 1969, and the prohibition imposed by section 89 of that Act" in paragraph (b) there were substituted the words " section 12(1) of the British Telecommunications Act 1981. and the prohibition imposed by section 89 of the Post Office Act 1969 ".