Part 2—General provisions relating to requests by the ICC for cooperation
8 How requests for cooperation are to be made
(1) Subject to section 9, a request for cooperation is to be made in writing:
(a) to the Attorney General through the diplomatic channel; or
(b) through the International Criminal Police Organisation or any other appropriate regional organisation.
(2) If a request for cooperation is sent to, or received by, a person to whom the Attorney General has delegated a power to deal with the request, the request is taken for the purposes of this Act to have been sent to, or received by, the Attorney General.
EDIT.