3(1)Without prejudice to paragraph 2 above, the court by which a probation order was made or the appropriate court may, upon application made by the officer supervising the probationer or by the probationer, subject to sub-paragraph (2) below, by order amend a probation order by cancelling any of the requirements thereof or by inserting therein (either in addition to or in substitution for any such requirement) any requirement which could be included in the order if it were then being made by that court in accordance with sections 228 to 230 of this Act.
(2)The court shall not amend a probation order under sub-paragraph (1) above—
(a)by reducing the probation period, or by extending that period beyond the end of three years from the date of the original order;
(b)so that the probationer is thereby required to reside in any institution or place, or to submit to treatment for his mental condition, for any period or periods exceeding 12 months in all;
(c)by inserting in it a requirement that the probationer shall submit to treatment for his mental condition unless the amending order is made within three months after the date of the original order.