26.—(1) An electricity supplier may dispute any determination made by the revenue collection counterparty under these Regulations, other than a determination made under or by virtue of regulation 27 of these Regulations, by giving a notice to the revenue collection counterparty setting out—
(a)the determination the supplier is disputing; and
(b)the basis on which the supplier disputes the determination.
(2) For the purposes of paragraph (1), a dispute about a determination made by the revenue collection counterparty includes a dispute about the failure of the revenue collection counterparty to make a determination.
(3) A notice under paragraph (1) must be given by an electricity supplier before the later of—
(a)the 28th day after the day on which the determination was made by the revenue collection counterparty;
(b)in the case of a determination in respect of which the revenue collection counterparty must issue a notice, the 28th day after the day on which that notice was issued;
(c)in the case of a dispute about the failure of the revenue collection counterparty to make a determination, the 28th day after the day on which the revenue collection counterparty should have made the relevant determination which is in dispute.
(4) An electricity supplier may not dispute a determination if and to the extent that the dispute is about a determination, made by the BSCCo, of an amount of electricity supplied (whether by that supplier or any other supplier).
(5) Where an electricity supplier has given a notice under paragraph (1) in respect of a determination, that determination still has effect notwithstanding the giving of that notice.