5. The conditions to be fulfilled by a person referred to in paragraph 4 of this Order are—

(a) he shall claim a refund of the tax by completing such claim form as may be provided for the purpose by the Revenue Commissioners and he shall certify the particulars shown on such form to be correct;

(b) he shall establish that he is a person to whom this Order applies and that the instruments or appliances on the supply or importation of which the tax was borne or paid by him were used by him in the capacity in relation to which this Order applies to him;

(c) he shall establish, by the production of invoices, provided in accordance with section 17 (12) (a) (i) of the Act, or by the production of receipts for tax paid on imported goods, the amount of tax borne or paid by him in relation to the goods specified in paragraph 4 of this Order;

(d) he shall establish that he is not entitled to a deduction under section 12 of the Act for any portion of the tax specified in subparagraph (c) of this paragraph.