There is limited evidence available in relation to some of these considerations and I am grateful to the sector for providing additional information they have gathered from their members.
Prin yw’r dystiolaeth sydd ar gael mewn perthynas â rhai o’r ystyriaethau hyn ac rwy’n ddiolchgar i’r sector am ddarparu gwybodaeth ychwanegol y maent wedi’i chasglu gan eu haelodau.