Subject to the provisions of this section—
Subsection (1)(a) of this section shall not apply to proceedings brought under section 89(5) of this Act against a person who—
Subject to subsection (4) of this section, the validity of a notice which has been served under section 65 of this Act on the owner and occupier of the land shall not, except by way of an appeal under Part V of this Act, be questioned in any proceedings whatsoever on any of the grounds specified in section 105(1)(a) to (c) of this Act.
Subsection (3) of this section shall not apply to proceedings brought under section 104 of this Act against a person on whom the notice referred to in that subsection was not served, but who has held an interest in the land since before that notice was served on the owner and occupier of the land, if he did not appeal against the notice under Part V of this Act.
The validity of a notice purporting to be an enforcement notice shall not depend on whether any non-compliance to which the notice relates was a non-compliance with conditions, or with limitations, or with both; and any reference in such a notice to non-compliance with conditions or limitations (whether both expressions are used in the notice or only one of them) shall be construed as a reference to non-compliance with conditions, or with limitations, or both with conditions and limitations, as the case may require.