5(1)A Minister of the Crown may by order amend this Schedule so as to add, vary or omit an exception to section 149.
(2)But provision by virtue of sub-paragraph (1) may not amend this Schedule—
(a)so as to omit an exception in paragraph 3;
(b)so as to omit an exception in paragraph 4(1) so far as applying for the purposes of paragraph 4(2)(a) to (e) or (3);
(c)so as to reduce the extent to which an exception referred to in paragraph (a) or (b) applies.