The producers are audited and the base UK inventory is subject to a rigorous annual programme of expert reviews (UN, EU), and frequent bilateral and peer reviews.
Mae’r cynhyrchwyr yn cael eu harchwilio ac mae rhestr sylfaenol y Deyrnas Unedig yn destun rhaglen o adolygiadau arbenigol blynyddol trylwyr (CU, UE), ac adolygiadau dwyochrog a chyfoed mynych.