(1) The Principal Act is hereby amended by the insertion after section 215A (inserted by section 38 of the Act of 1990) of the following section:
"215B. Recoupment of supplementary welfare allowance.
Where -
(a) in respect of any period a health board has granted supplementary welfare allowance to or in respect of a person who, though entitled to any other benefit, pension, assistance, allowance or supplement under this Act (in this section referred to as 'relevant payment'), is not in receipt of such relevant payment, and
(b) such supplementary welfare allowance is in excess of the amount which would have been granted to that person if he had been in receipt of such relevant payment, and
(c) any relevant payment accruing in respect of any part of the same period (in this section referred to as 'the arrears') subsequently becomes payable to that person, and
(d) the health board has, before the arrears are paid to that person, certified to the Minister the amount (in this section