9.—(1) Sums payable under a maintenance decision enforceable in the United Kingdom by virtue of the Maintenance Regulation, including any arrears so payable, shall be paid in sterling where an order is made on an application for enforcement in England and Wales, Scotland or Northern Ireland.
(2) Where the maintenance decision is expressed in any other currency, the amount shall be converted on the basis of the exchange rate prevailing on the date on which the application for enforcement or registration of the decision was received by a Central Authority in the United Kingdom for transmission to a court.
(3) For the purposes of this paragraph, a written certificate purporting to be signed by an officer of any bank in the United Kingdom and stating the exchange rate prevailing on a specified date shall be evidence of the facts stated (and in Scotland, sufficient evidence of those facts).