Information is exempt information if it consists of instructions for the guidance of officers of a public authority on the processes to be followed or the criteria to be applied –

(a) in negotiations, including financial, commercial and labour negotiations; or

(b) in the execution of contracts; or

(c) in the defence, prosecution and settlement of cases; or

(d) in similar activities –

relating to the financial, property or personnel management and assessment interests of the Crown or of a public authority.