10. If, in relation to an offence under regulation 13(c) or 14—
(a)a variable monetary penalty is imposed on any person, or
(b)a third party undertaking is accepted from any person,
that person may not at any time be convicted of the offence in respect of the act or omission giving rise to the variable monetary penalty or third party undertaking except in a case to which paragraph 11(1)(b) applies.