30   Duration of orders for periodic maintenance

(1)  An order under this Part for periodic maintenance, being an order made where a court is satisfied solely as to the matters specified in section 27 (1) (a), may apply for such period as may be determined by the court, not exceeding the period expiring when the child to whom section 27 (1) (a) applies, or the younger or youngest such child, as the case may require:

(a)  except in the case of a child referred to in paragraph (b)—attains the age of 12 years, or

(b)  in the case of a physically handicapped child or mentally handicapped child—attains the age of 16 years.

(2)  An order under this Part for periodic maintenance, being an order made where a court is satisfied solely as to the matters specified in section 27 (1) (b), may apply for such period as may be determined by the court, not exceeding:

(a)  3 years after the day on which the order is made, or

(b)  4 years after the day on which the relationship ceased, or last ceased,

      whichever is the shorter.

(3)  An order under this Part for periodic maintenance, being an order made where a court is satisfied as to the matters specified in section 27 (1) (a) and (b), may apply for such period as may be determined by the court, not exceeding the period permissible under subsection (1) or (2), whichever is the longer.

(4)  Nothing in this section or an order under this Part for periodic maintenance prevents such an order from ceasing to have effect pursuant to section 32 or 33.