ARTG11030 - Resolution of appeal: payment of tax following an appeal
Where tax is due following the outcome of an appeal is the amount originally charged, interest is chargeable on any unpaid tax from the original due date.
Payment of additional tax
Where the amount of tax due following resolution of the appeal is greater than the amount originally charged, any additional tax will become due and payable 30 days after the tax payable as a result of the amended decision is notified to the customer. Interest will also be chargeable on any additional tax unpaid from this date.
See CH141000+ or the guidance on late payment interest, but see CH140160 first to check which rules apply to the tax or duty you are dealing with.