3.—(1) No meter shall be used for ascertaining the quantity of electricity supplied by an electricity supplier to a customer unless the meter—
(a)is of an approved pattern or construction and is installed in an approved manner; and
(b)subject to sub-paragraph (2), is certified under paragraph 6.
(2) Sub-paragraph (1)(b) shall not apply to a meter used in connection with an exempt supply if the electricity supplier and the customer have agreed in writing to dispense with the requirements of that paragraph.
(3) Regulations under this paragraph may provide—
(a)for determining the fees to be paid in connection with applications for approvals under the regulations;
(b)for revoking such an approval to any particular pattern or construction of meter and requiring meters of that pattern or construction which have been installed to be replaced with meters of an approved pattern or construction within a prescribed period;
(c)for revoking such an approval to any particular manner of installation and requiring meters which have been installed in that manner to be installed in an approved manner within such a period.