(a) it shall not, unless it is expressly so provided, be necessary to prove guilty knowledge;

(b) the onus of proving the place of origin of goods, or the payment of the proper duties, or the lawful importation, landing, removal, conveyance, exportation or carriage coastwise of goods, or the place of manufacture of excisable goods, or that spirits in respect of which duty has been remitted for a particular purpose have been used for that purpose, or the payment of the proper duties, or the lawful manufacture of excisable goods, or that any materials or plant have been unlawfully seized, shall be on the person prosecuted or claiming anything seized under this Act;

(c) the averment by the Commissioner-

(i) that a person is or was an officer or is or was employed in the prevention of smuggling, or that an act was performed by an officer in the execution of his duty;

(ii) that any goods were staved, broken, destroyed, rescued or thrown overboard, or were so staved, broken, destroyed, rescued or thrown overboard for the purpose of preventing the seizure thereof or the securing thereof after seizure;

(iii) that any act was done within the limits of a port or at, in or over any part of Kenya;

(iv) that the Commissioner, or an officer, is or is not satisfied as to any matter as to which he is required to be satisfied under this Act:

(v) that the Commissioner has directed or requested proceedings under this Act to be instituted, shall be prima facie evidence of that fact;

(d) a certificate purporting to be signed by or on behalf of the Government Analyst or the Government Chemist shall be receivable in evidence and shall be prima facie evidence of the matters recorded therein;

(e) the production of a document purporting to be signed or issued by the Commissioner or any person in the service of the Government shall be prima facie evidence that the document was so signed or issued;

(f) a copy, certified under the hand of the Commissioner, of an entry in a book or document required to be kept for the purposes of this Act shall be receivable in evidence and shall be prima facie evidence of the entry and of the matters recorded therein;

(g) any information, communication, certificate, official report or other document purporting to originate from or to be certified under the hand and seal or stamp of office of a principal officer of customs and excise or of any other competent authority in a foreign country and produced by the Commissioner shall be receivable in evidence and shall be prima facie evidence of the matters communicated or recorded therein;

(h) a certificate or a copy of a document or publication purporting to be signed or issued by or under the authority of the Customs Co-operation Council (established by an international convention at Brussels on 15th December, 1950) and produced by the Commissioner shall be receivable in evidence and shall be prima facie evidence of the matters contained therein;

(i) any information, communication or certificate or a copy of a document purporting to be signed or issued by or under the authority of any institution, organization or firm recognized and authorized by the Government under any agreement and produced by the Commissioner shall be receivable in evidence and shall be prima facie evidence of the matters communicated or contained therein;

(j) an officer shall be a competent witness notwithstanding that he is entitled to a reward;

(k) the fact that security has been given by bond or otherwise for the payment of duty or for the compliance with any condition in respect of the non-payment of which or non-compliance with which the proceedings are brought shall not be a defence.