10.—(1) A head to whom a request under section 7 is made may refuse to grant the request if—

(a) the record concerned does not exist or cannot be found after all reasonable steps to ascertain its whereabouts have been taken,

(b) the request does not comply with section 7 (1) (b),

(c) in the opinion of the head, granting the request would, by reason of the number or nature of the records concerned or the nature of the information concerned, require the retrieval and examination of such number of records or an examination of such kind of the records concerned as to cause a substantial and unreasonable interference with or disruption of F15[…] work of the public body concerned,

(d) publication of the record is required by law and is intended to be effected not later than 12 weeks after the receipt of the request by the head,

(e) the request is, in the opinion of the head, frivolous or vexatious F16[, or forms part of a pattern of manifestly unreasonable requests from the same requester or from different requesters who, in the opinion of the head, appear to have made the requests acting in concert], or

(f) a fee or deposit payable under section 47 F16[in respect of the request concerned or in respect of a previous request by the same requester] has not been paid.

(2) A head shall not refuse, pursuant to paragraph (b) or (c) of subsection (1), to grant a request under section 7 unless he or she has assisted, or offered to assist, the requester concerned in an endeavour so to amend the request that it no longer falls within that paragraph.