Rhaid i bob sefydliad trwyddedig benodi unigolyn dynodedig y mae arno ddyletswydd gyfreithiol i sicrhau bod gofynion statudol a rheoleiddiol yn cael eu bodloni. Mae'n gyfrifol am oruchwylio gweithgareddau trwyddedig a sicrhau bod yr arferion priodol ar waith.
All licensed establishments must appoint a DI who has a legal duty to ensure that statutory and regulatory requirements are met. They are responsible for supervising licensed activities and ensuring suitable practices are taking place.