6.—(1) The council may vary a Part 4 notice in accordance with this paragraph.
(2) A notice may be varied—
(a)on an application by any person on whom the notice was required to be served under paragraph 1(1), or
(b)on the council’s own initiative.
(3) The date specified (as the date by which work must be completed) in—
(a)a statement of remedial work under section 53, or
(b)a works requirement in a hazard notice,
may not be varied under this paragraph (but see paragraph 3 of Schedule 3).
(4) If a council varies a Part 4 notice, the council must serve, on each person on whom the notice was required to be served under paragraph 1(1), notice of the variation, accompanied by a copy of the notice as varied.
(5) If a person applies for a variation of a Part 4 notice but the council decides to refuse it, the council must serve, on each person on whom the notice was required to be served under paragraph 1(1), notice of that refusal.
(6) If a notice is varied with the agreement of every person on whom the notice was required to be served under paragraph 1(1), the variation has effect from the date on which it is made.
(7) Otherwise a variation does not have effect until—
(a)the last date on which the decision to vary the notice may be appealed in accordance with section 67(4), or
(b)where such an appeal is made, the date on which the appeal is finally determined.