31.— (1) The calculation and payment of any retirement benefit which falls due to be paid under this Chapter, shall be a function of—

(a) the relevant authority for the public service body in which the person concerned was last serving before retirement as a public servant and in respect of which he or she was a Scheme member, or

(b) such other relevant authority that the Minister has directed in writing to carry out such function, either generally or in respect of any class or classes of former Scheme members.

(2) Nothing in subsection (1) shall be read so as to prevent the relevant authority making arrangements for the payment as its agent of any retirement benefit through another relevant authority or a third party.