30.—(1) A head may refuse to grant a request under section 7 if, in the opinion of the head—

(a) the record concerned contains information in relation to research being or to be carried out by or on behalf of a public body and disclosure of the information or its disclosure before the completion of the research would be likely to expose the body, any person who is or will be carrying out the research on behalf of the body or the subject matter of the research to serious disadvantage, or

(b) disclosure of information contained in the record could reasonably be expected to prejudice the well-being of a cultural, heritage or natural resource or a species, or the habitat of a species, of flora or fauna.

(2) Subsection (1) does not apply in relation to a case in which, in the opinion of the head concerned, the public interest would, on balance, be better served by granting than by refusing to grant the request under section 7 concerned.