24.—It shall not be a defence for a person charged with an offence under section 49 (1) or 50 (1) of the Principal Act to show that, in relation to the facts alleged to constitute the offence, an analysis or determination under the Road Traffic Acts, 1961 to 1994, has not been carried out or that he has not been requested under F28[section 12 of this Act or section 4 of the Road Traffic Act 2006] to provide a specimen of his breath.