In Scotland the two crew would have had a second test done most likely a blood sample at the station. There’s also a requirement in Scotland of corroboration (differs from rUK) so two pieces of evidence the initial breathalyser test and then the 2nd test will be presented to the Procurator Fiscal. It’ll be the PF’s decision to instruct Police Scotland to Charge the crew. There would be a hearing done at the Sheriff (a Judge not a Law Officer as in the US) Court where the PF will present the evidence and Sheriff will decide wether the case proceeds and if they accused will be bailed. Scots drink drive limit is also lower than the rUK at EU average of 50mg/l in specimen of breath.