Lines are open Monday to Thursday (excluding bank holidays), 9am to 4:45pm and Friday (excluding bank holidays), 9am to 4:30pm.
Mae'r llinellau ar agor o ddydd Llun tan ddydd Iau (ac eithrio gwyliau banc), 9am i 4:45pm a dydd Gwener (ac eithrio gwyliau banc), rhwng 9am a 4:30pm.