24. (1) The Controller shall not vary, or suspend or cancel a licence under section 23, unless he or she has given to the licensee a notice in writing that—
(a) specifies the ground upon which the Controller intends to vary, suspend or cancel the licence;
(b) states the facts and circumstances that, in the Controller's opinion, constitute that ground; and
(c) informs the licensee that the licensee may, within 28 days after the date of the notice, give to the Controller a written response to the matters stated in the notice.
(2) For the purpose of deciding whether to exercise his or her powers under section 22 or 23, the Controller shall have regard to any response given in accordance with a notice under subsection (1).