Looking back to your querry I noticed
a) Your assessment was completed after a delay of one year
In this regard please note the law provide for various time limits to finish/complete/finalise assessment beyond that it becomes time barred. In case your assessment is not invalid and time barred by limitation, the same has been completed within the permissible time available under the law and you are not entitled any interest beyond as prescribed under section 244A. The department must have paid you that. In case of any short fall or deficiency in that you may move application u/s 154 for rectification of interest calculation before jurisdictional assessing officer.
b) Your refund was further delayed by one year after assessment.
The department is bound to issue refund/demand notice alongwith assessment order and pay interest as prescribed under section 244A of the Income-tax Act.
The act itself is sovergn and enjoys immunity. There is no precedence in my knowledge where in a Writ the Court has directed the Department to pay punitive interest.