Mae fy Ngrŵp Cynghorol Trethi - sy’n cynnwys cynrychiolwyr o fyd busnes, TUC Cymru, y trydydd sector, llywodraeth leol,  a’r proffesiynau cyfrifyddu a chyfreithiol, ynghyd â thri aelod arbenigol - wedi bod yn ffynhonnell werthfawr arall o gyngor.  Ystyriaeth allweddol sydd wedi deillio o’r Grŵp fu pwysigrwydd sicrhau bod unrhyw gorff sy’n ymwneud â chasglu a rheoli trethi datganoledig yn cael ei ddal i gyfrif yn briodol am safonau’r gwasanaethau y maent yn eu cyflawni.
My Tax Advisory Group – which includes representatives from business, the Wales TUC, the third sector, local government,  and the accounting and legal professions, along with three expert members – has been another valuable source of advice.  A key consideration emerging from the Group has been the importance of ensuring that any organisation involved in the collection and management of devolved taxes is held appropriately to account for the service standards that they achieve.