law: 470. Limitation of time for prosecution.
  No person shall be liable to punishment for any offence against this Act or any rule, regulation or by-law made thereunder, unless complaint of such offence is made before a municipal magistrate within six months next after
  (a) the date of the commission of such offence, or
  (b) the date on which the commission or existence of such offence was first brought to the notice of the complainant.