16.—(1) No person shall install a prepayment meter as a primary meter through which gas passes to a secondary meter.
(2) Any person—
(a)who first provides gas through any service pipe or service pipework after the coming into force of these Regulations to more than one primary meter; or
(b)who subsequently makes any modification which affects the number of primary meters so provided,
shall ensure that a notice in permanent form is prominently displayed on or near each primary meter indicating that more than one primary meter is provided with gas through that service pipe or service pipework.
(3) Where a primary meter is removed, the person who last supplied gas through the meter before removal shall—
(a)where the meter is not forthwith re-installed or replaced by another meter—
(i)close any service valve which controlled the supply of gas to that meter and did not control the supply of gas to any other primary meter; and
(ii)seal the outlet of the emergency control with an appropriate fitting; and
(iii)clearly mark any live gas pipe in the premises in which the meter was installed to the effect that the pipe contains gas; and
(b)where the meter has not been re-installed or replaced by another meter before the expiry of the period of 12 months beginning with the date of removal of the meter and there is no such service valve as is mentioned in sub-paragraph (a)(i) above, ensure that the service pipe or service pipework for those premises is disconnected as near as is reasonably practicable to the main or storage vessel and that any part of the pipe or pipework which is not removed is sealed at both ends with the appropriate fitting.
(4) Where a person proposes to remove a primary meter he shall give sufficient notice of it to the person supplying gas through the meter to enable him to comply with paragraph (3).