(1) On the hearing of a charge for an offence under section 49 or 50 of the Principal Act, it shall not be necessary to show that the defendant had not consumed intoxicating liquor after the time when the offence is alleged to have been committed but before the taking or provision of a specimen under section 30 or section 33.
(2) Where, on the hearing of a charge for an offence under section 49 or 50 of the Principal Act, evidence is adduced by or on behalf of the defendant that, after the time when the offence is alleged to have been committed but before the taking or provision of a specimen under section 30 or section 33, he had consumed intoxicating liquor, the court shall disregard the evidence unless satisfied by or on behalf of the defendant that but for that consumption the concentration of alcohol in the defendant's blood (as specified in a certificate under section 43(3) or 45(2)) would not have exceeded a concentration of 125 milligrammes of alcohol per 100 millilitres o