3.—(1) An exemption shall have effect from the date of the giving of a notice in accordance with Article 2(2)(b) and shall continue unless and until terminated by the licensing authority under the provisions of paragraph (2).
(2) The licensing authority may terminate an exemption either wholly or so far as it relates to one or more descriptions or classes of contact lens substances, by giving notice in writing to the doctor, pharmacist or optician concerned where—
(a)it appears to the licensing authority at any time on grounds of safety that that exemption should cease to have effect; or
(b)that doctor, pharmacist or optician has been requested in writing by the licensing authority to inform them in writing which descriptions or classes of contact lens substances he has assembled under an exemption and has failed so to inform them within 21 days of the date of such request or within such further time as the licensing authority may in a particular case allow.
(3) The date from which an exemption terminated by a notice under paragraph (2) shall cease to have effect shall be the date on which such notice is given or such later date as may be specified in the notice.