7. Section 28F (agreement to a variation) shall be modified—
(a)by the substitution for subsection (3) of the following—
“(3)The Secretary of State shall not agree to a variation (and shall proceed to revise or supersede a decision under section 16 or 17 respectively without taking the variation into account, or not revise or supersede a decision under section 16 or 17) if he is satisfied that prescribed circumstances apply.”;
(b)by the omission in paragraph (a) of subsection (4) of the words after the word “application,” where it first appears;
(c)by the substitution for subsection (4)(b) of the following—
“(b)revise or supersede a decision under section 16 or 17 respectively on that basis.”; and
(d)by the omission of subsection (5).