(1)Subject to subsection (2) below, in their application to development authorised by this Act, article 3 of, and Class A in Part 11 of Schedule 2 to, the [S.I. 1988/1813.] Town and Country Planning General Development Order 1988 (which permit development authorised by private Act designating specifically both the nature of the development thereby authorised and land on which it may be carried out) shall have effect as if the authority to develop given by this Act were limited to such development begun within 10 years after the passing of this Act.
(2)Subsection (1) above shall not apply to the carrying out of any development consisting of the alteration, maintenance or repair of works or the substitution of new works therefor.