JL

Dear Sir/Madam, I would like to seek your advice on what I should do with my Self Assessment for Tax Year 2021/2022. My situation is as follows: The payroll service provider of my employer mistakenly used "Salary Sacrifice" in the pension calculation for Tax Year 2021/2022. The correct treatment should be "Relief At Source" as told by my employer. As such, my employer issued a revised payslip of Mar 2022 which includes all the net adjustments to reflect the correct the pension treatment as "Relief At Source". However, the revised payslip was just issued in Aug 2023 (months after the Self Assessment and Tax Payment deadline). I am wondering how I can retrospectively file an updated Self Assessment for Tax Year 2021/2022 because I have already submitted that Self Assessment and paid the corresponding tax in Jan 2023. In the updated Self Assessment, I need to do at least two things: (a) revise the pension payment and (b) claim the tax benefit (above the base rate) due to changing the treatment from "Salary Sacrifice" to "Relief At Source". Could you please tell me: (a) How to do a retro filing of revised Self Assessment for Tax Year 2021/2022? Which forms and/or boxes that I need to fill in? (b) Will this be treated as late submission of Self Assessment? What is the penalty? Look forward to hearing from you soon. Thank you.