Where an employer is charged with an offence punishable under this Act, he shall be entitled, upon complaint duly made by him and on giving to the complainant not less than three clear days' notice in writing of his intention to do so, to have any other person whom he charges as the actual offender brought before the court at the time appointed for hearing the charge; and if, after the commission of the offence has been proved, the employer proves to the satisfaction of the court--
         (a) that he has used due diligence to enforce the execution of this Act, and
         (b) that the said other person committed the offence in question without his knowledge, consent or connivance,
     that other person shall be convicted of the offence and shall be liable to the like punishment as if he were the employer and the employer shall be discharged from any liability under this Act in respect of such offence:
     Provided that in seeking to prove as aforesaid, the employer may be examined on oath and his evidence and that of any witness whom he calls in his support shall be subject to cross-examination on behalf of the person he charges as the actual offender and by the prosecutor:
     Provided further that, if the person charged as the actual offender by the employer cannot be brought before the court at the time appointed for hearing the charge, the court shall adjourn the hearing from time to time for a period not exceeding three months and if by the end of the said period the person charged as the actual offender cannot still be brought before the court, the court shall proceed to hear the charge against the employer and shall, if the offence be proved, convict the employer.