18(1)Subsection (3) of section 58 of this Act shall not apply to any treatment given to a patient in the period of six months beginning with 30th September 1983 if—
(a)the detention of the patient began before the beginning of that period; and
(b)that subsection has not been complied with in respect of any treatment previously given to him in that period.
(2)The Secretary of State may by order reduce the length of the period mentioned in sub-paragraph (1) above.