My friend was in a Road Traffic accident, and was breathalysed when the police arrived,and back at the station. BEFORE being breathalysed at the station, he noticed that the machine purge was 35 and, after, it was 34. He blew a 77 then an 80.It seems to him that the machine hadn't been purged properly since its last use ,and wonders if this could have an effect on his result? also could this be used as a defence in court? He has to represent him self as he works so is not entitled to legal aid but can't afford to hire legal council.