5.—(1) A manufacturer may demonstrate that a meter measuring system is compliant with the essential requirements by—
(a)using any technical solution that is compliant with the essential requirements;
(b)correctly applying solutions set out in the relevant national standard; or
(c)correctly applying solutions set out in the relevant normative document,
and selecting and following one of the conformity assessment procedures.
(2) A meter measuring system which is compliant with the relevant national standard or relevant normative document shall be presumed to be compliant with the essential requirements.
(3) Where the meter measuring system is compliant only in part with the relevant national standard or relevant normative document, it shall be presumed to be compliant only with that part of the essential requirements which corresponds to the element of the relevant national standard or relevant normative document with which the instrument is compliant.
(4) Where a meter measuring system includes or is connected to a device which is not used for trade—
(a)that device shall not be subject to the essential requirements; and
(b)the instrument may be considered to be compliant with the essential requirements notwithstanding that the compliance of that device with the essential requirements has not been established.