(1) In a prosecution for refusing or failing to permit a designated registered medical practitioner to take a specimen of blood, it shall be a good defence for the defendant -
(a) to show that, when brought to the Garda station and before a requisition under section 30(1)(b) or section 33(1)(b) was made on him, he was not given an opportunity by a member of the Garda Síochána (having requested such an opportunity of such a member) of providing in the prescribed manner a specimen of his breath by exhaling into an apparatus designed for the purpose of indicating the presence of alcohol in the breath, or
(b) to show that, when required to permit the taking of the specimen, he had not been cautioned in the prescribed terms of the possible effects of his refusal or failure, or
(c) to satisfy the court that there was a special and substantial reason for his refusal or failure.
(2) Notwithstanding subsection (1)(c), on the hearing of a charge for an offence under section 49 or 50 of