15.—(1) An authorisation given by virtue of this Part, or any provision amended by Part IV, may authorise the exercise of a function—
(a)either wholly or to such extent as may be specified in the authorisation;
(b)either generally or in such cases or areas as may be so q specified; and
(c)either unconditionally or subject to the fulfilment of such conditions as may be so specified.
(2) An authorisation given by virtue of this Part, or any provision amended by Part IV—
(a)shall be for such period, not exceeding 10 years, as is specified in the authorisation;
(b)may be revoked at any time by the Department or person by whom the authorisation is given; and
(c)does not prevent that Department or any other person from exercising the function to which the authorisation relates.