On an appeal under section 174 the Secretary of State may—
if he is satisfied that the correction or variation will not cause injustice to the appellant or the local planning authority.
Where the Secretary of State determines to allow the appeal, he may quash the notice.
The Secretary of State shall give any directions necessary to give effect to his determination on the appeal.
The Secretary of State—
If section 175(3) would otherwise apply and the Secretary of State proposes to dismiss an appeal under paragraph (a) of subsection (3) of this section or to allow an appeal and quash the enforcement notice under paragraph (b) of that subsection, he need not comply with section 175(3).
Where it would otherwise be a ground for determining an appeal under section 174 in favour of the appellant that a person required to be served with a copy of the enforcement notice was not served, the Secretary of State may disregard that fact if neither the appellant nor that person has been substantially prejudiced by the failure to serve him.
If at any time before or during the determination of an appeal against an enforcement notice issued by a local planning authority in England it appears to the Secretary of State that the appellant is responsible for undue delay in the progress of the appeal, the Secretary of State may—