(1) A head may delegate in writing to a member of the staff of the public body concerned any of the functions of the head under this Act (other than this section and section 25).
(2) A delegation under subsection (1) ("a delegation") may -
(a) relate to functions generally or specified functions or be in respect of records generally or specified classes of records or specified records, and
(b) be to a specified member or specified members of the staff of the public body concerned or to such members who are of a specified rank or grade or of a rank or grade not lower than a specified rank or grade,
and may delegate different functions or classes of function to different such members or classes of members.
(3) A delegation may be revoked in whole or in part or amended in writing by the head for the time being of the public body concerned.
(4) A delegation shall operate, so long as it continues in force, to confer on and vest in the person concerned the function or functions delegate