23.— (1) A member of the Garda Síochána not below the rank of superintendent may, by notice in writing, authorise a person to do a thing referred to in section 7(1) if the member is satisfied that the thing is necessary for the purposes of an investigation into an offence.

(2) The doing of any thing in accordance with an authorisation under this section shall not be treated, for any purpose, as a breach of any requirement or restriction imposed by any other enactment or rule of law.

(3) Subsection (2) is without prejudice to section 7 (7).