23.— The Executive may, at its discretion and subject to such conditions as it considers appropriate, make arrangements to supply an item, pursuant to F2[section 59, 62A or 67E] of the Act of 1970, to a patient notwithstanding that the item is not a listed item if the Executive is satisfied that—

(a) the patient requires that item for clinical reasons, and

(b) there is no listed item which is a suitable alternative for that item in so far as that patient is concerned.