There is no legal requirement to provide feedback of this nature but it may be particularly useful for small and medium-sized enterprises or new entrants to the market.
Nid oes gofyniad cyfreithiol i roi adborth o'r fath ond gall fod yn arbennig o ddefnyddiol i fusnesau bach a chanolig eu maint neu newydd-ddyfodiaid i'r farchnad.