The Secretary of State may give guidance about anything that could be done under or by virtue of this Chapter by an authority to whom this section applies.

An authority to whom this section applies must have regard to any guidance given under this section in exercising any function conferred or imposed by or by virtue of this Chapter.

Any guidance under this section must be given in writing and may be varied or revoked by further guidance in writing.

Any such guidance may make different provision for different cases and different provision for different areas.