5.—(1) Each of the contributing authorities shall pay to the Secretary of State the charge for which a demand is issued to them under article 3 of this Scheme in respect of the first accounting period either, at their option, by one lump sum payment which shall become due on 1st April 1982 or by four equal instalments which shall become due respectively on 1st April, 1st July and 1st October 1982 and 3rd January 1983.
(2) Each of the contributing authorities shall pay to the Secretary of State the charge for which a demand is issued to them under article 3 of this Scheme in respect of an accounting period other than the first either, at their option, by one lump sum payment which shall become due at the beginning of the accounting period or by four equal instalments which shall become due respectively on 1st April, 1st July, 1st October and 3rd January in the accounting period.
(3) If a contributing authority who have decided to pay the charge for which a demand has been issued to them under article 3 of this Scheme by four equal instalments fail to pay the first, second or third instalment within a period of 14 days beginning with the day when that instalment became due in accordance with the preceding provisions of this article, then upon the expiration of the said period the whole amount of the said charge or, as the case may be, of the balance thereof then outstanding, shall become due and payable to the Secretary of State.
(4) The amount of any payment to be made by a contributing authority under the preceding provisions of this article shall be a debt due by that authority to the Secretary of State. Unless a contributing authority have indicated to the Secretary of State that they have decided to pay the charge for which a demand has been issued to them under article 3 of this Scheme by one lump sum payment it shall be assumed for the purposes of this paragraph that a contributing authority have decided to pay such charge by four equal instalments.