Sch 9ZA para 12
(1) Subject to the following provisions of this paragraph, where— (a) goods are acquired from a member State, and (b) any sum relevant for determining the value of the relevant transaction is expressed in a currency other than sterling, then, for the purpose of valuing the relevant transaction, that sum is to be converted into sterling at the market rate which, on the relevant day, would apply in the United Kingdom to a purchase with sterling of that sum in the currency in question by the person making the acquisition. (2) Where the Commissioners have published a notice which, for the purposes of this paragraph, specifies— (a) rates of exchange, or (b) methods of determining rates of exchange, a rate specified in or determined in accordance with the notice, as for the time being in force, applies (instead of the rate for which sub-paragraph (1) provides) in the case of any transaction in pursuance of which goods are acquired by a person who opts, in such manner as may be allowed by the Commissioners, for the use of that rate in relation to that transaction. (3) An option for the purposes of sub-paragraph (2) for the use of a particular rate or method of determining a rate— (a) may not be exercised by any person except in relation to all such transactions in pursuance of which goods are acquired by the person from a member State as are of a particular description or after a particular date, and (b) may not be withdrawn or varied except with the consent of the Commissioners and in such manner as they may require. (4) In specifying a method of determining a rate of exchange, a notice published by the Commissioners under sub-paragraph (2) may allow a person to apply to the Commissioners for the use, for the purpose of valuing some or all of the transactions in pursuance of which goods are acquired by the person from a member State, of a rate of exchange which is different from any which would otherwise apply. (5) On an application made in accordance with provision contained in a notice under sub-paragraph (4), the Commissioners may authorise the use with respect to the applicant of such a rate of exchange, in such circumstances, in relation to such transactions and subject to such conditions as they think fit. (6) A notice published by the Commissioners for the purposes of this paragraph may be withdrawn or varied by a subsequent notice published by the Commissioners. (7) Where goods are acquired from a member State, the appropriate rate of exchange is to be determined for the purpose of valuing the relevant transaction by reference to the relevant time; and, accordingly, the day on which that time falls is the relevant day for the purposes of sub-paragraph (1).