10Deferment of tests and modification of test standards
(1)An order under section 9 of this Act (referred to below in this Part of this Act as an " on-site testing order ") may provide that the relevant testing authority may, in such circumstances as may be specified in the order, defer carrying out any test applied for under that order until after the end of the initial period allowed for testing in accordance with subsection (1) of that section; but where a test is so deferred—
(a)any prohibition imposed by virtue of that subsection shall have effect in relation to the heat generator in question by reference to such period, not exceeding a maximum period of deferment specified in the order, as the authority may allow in substitution for that initial period; and
(b)any prohibition imposed by virtue of subsection (2) of that section shall apply as if the substitute period so allowed were that initial period.
(2)An on-site testing order may provide that the relevant testing authority may apply such modified standards of efficiency as the authority thinks fit in carrying out tests in such circumstances as may be specified in the order ; and in any case where modified standards are applied by virtue of any such provision, any prohibition imposed by virtue of section 9(2) shall apply (subject to subsection (4)(b) below) by reference to the modified standards.
(3)In any such case an on-site testing order may prohibit the further use, in such circumstances as may be specified in the order, after the end of a period so specified beginning with the date on which its use in those circumstances is begun, of any generator tested according to modified standards, unless its efficiency is tested during that period according to the standards of efficiency applicable under the order in the case of that generator apart from any provision made by virtue of subsection (2) above.
(4)In any case within subsection (3) above any prohibition imposed by virtue of section 9(2) shall apply—
(a)as if the period specified by virtue of subsection (3) above were the initial period mentioned in section 9(2); and
(b)without modification by subsection (2) above.
(5)The Secretary of State may give testing authorities general directions as to the manner in which they are to exercise any power to defer tests or to apply modified standards conferred on them by virtue of this section; and it shall be the duty of testing authorities to comply with any directions so given.