21.—(1) The amount of the penalty charge is recoverable from the recipient of the penalty charge notice as a debt owed to the enforcement authority unless–
(a)the notice has been withdrawn or quashed; or
(b)the charge has been paid.
(2) Proceedings for the recovery of the penalty charge notice may not be commenced–
(a)before the end of the period specified in accordance with regulation 17(3)(d); and
(b)if within that period the recipient of the penalty charge notice gives notice to the authority requesting the authority to review the penalty charge notice, such proceedings may not be commenced–
(i)before the end of the period mentioned in regulation 20(2); and
(ii)where the recipient appeals against the penalty charge notice, before the end of the period of 28 days beginning with the day on which the appeal is withdrawn or determined by the sheriff.
(3) In proceedings for the recovery of the penalty charge, a certificate which–
(a)purports to be signed by or on behalf of the person having responsibility for the financial affairs of the enforcement authority; and
(b)states that payment of the penalty charge was or was not received by a date specified in the certificate,
is evidence of the facts stated.