They all must have a poster (and notify DVSA) of their opening days and hours. There are two columns on that poster giving the days and times for 'tests by appointment' and 'tests on demand'. Most places just say 'by appointment only' but will do one straight away if they are not busy. Not many actually offer tests on demand.Thanks for that. I am not much of a regulations reader. Is it mandatory that they must offer a while you wait service? They are all very keen to have the car left with them. I know a local one that insists on it or not do the job.