then, without affecting the admissibility of any evidence which might be given apart from the provisions of this section, evidence may be given of the taking, after that person drove or was in charge of a motor vehicle, of a sample of blood from that person by a registered medical practitioner or an approved health professional, of the analysis of that sample of blood by a properly qualified analyst within twelve months after it was taken, of the presence of alcohol or any other drug and, if alcohol is present, of the concentration of alcohol expressed in grams per 100 millilitres of blood found by that analyst to be present in that sample of blood at the time of analysis and, if a drug is present, evidence may be given by a properly qualified expert of the usual effect of that drug on behaviour when consumed or used (including its effect on a person's ability to drive properly).