Fieldwork was halted in mid March 2020, due to the coronavirus outbreak (but fieldwork for 2019-20 was already almost complete at that point).
Cafodd y gwaith maes ei atal yng nghanol mis Mawrth 2020 oherwydd yr achosion o coronafeirws (ond roedd gwaith maes 2019-20 bron wedi’i gwblhau erbyn hynny).