24.—(1) Where, in a prosecution for an offence under the Principal Act, the existence or non-existence of a firearm certificate, a licence under section 17 of the Principal Act, an authorisation under section 2 of the Principal Act, a permit under section 3 of this Act or an authorisation under section 13 of this Act is material, it shall not be necessary to prove that the certificate, licence, authorisation or permit does not exist.

(2) Where, in a prosecution for an offence under the Principal Act, possession, use or carriage of a firearm or ammunition by a person is proved, it shall not be necessary to prove that the person was not entitled to have in his possession, use or carry a firearm or ammunition.