If you are late, UNDER NO CIRCUMSTANCES should you attempt to gain entry to either the theory or practical examination. In addition, you must never try gain entry by knocking on doors, ringing bells or banging on the workshops shutters.
If you are late, the examination has already begun, and the examiners have no way of dealing with you. They are conducting examinations and if you attempt to contact them or to gain entry, you are disrupting those examinations. Such behaviour will immediately attract disciplinary action.
If you are late for an examination, the procedure is that you should wait until the examination is over and the examiner is free to deal with you. Make yourself known to them, and explain that you were late.