3. A body of persons which establishes to the satisfaction of the Revenue Commissioners that it has borne or paid tax in relation to—

(a) the supply or hire to it,

(b) the intra-Community acquisition or importation by it, or

(c) the repair, modification or maintenance for it,

of a boat or similar craft of a gross tonnage of 15 tons or less, designed and constructed, or adapted, for the purpose of rescue or assistance at sea or on inland waterways, of equipment for use in or in conjunction with any such boat or craft, or of a building or structure for housing or operating such boat, craft or equipment, and which fulfils to the satisfaction of the Revenue Commissioners the conditions specified in Article 5 shall be entitled to be repaid such tax.