Following submission of that return, the taxpayer has 12 months from the filing date of the return within which to amend the return to provide an accurate figure for rents payable.
Ar ôl cyflwyno’r ffurflen dreth honno, mae gan y trethdalwr 12 mis o ddyddiad ffeilio'r ffurflen dreth i newid y ffurflen dreth i roi ffigur cywir ar gyfer y rhenti sy’n daladwy.