23. (1) Where—

(a) an application for the review by the Commissioner of—

(i) a decision to refuse to grant an FOI request, or

(ii) a decision under section 21 in relation to a decision referred to in subparagraph (i),

is made under section 22, and

(b) the Commissioner considers that the statement of the reasons for the decision referred to in paragraph (a)(i) in the notice under subsection (1) of section 13 or of the findings or particulars referred to in subsection (2)(d)(ii) of that section in relation to the matter is not adequate,

the Commissioner shall direct the head concerned to furnish to the requester concerned and the Commissioner a statement, in writing or such other form as may be determined, containing any further information in relation to those matters that is in the power or control of the head.

(2) A head shall comply with a direction under this section as soon as may be, but not later than 3 weeks, after its receipt.