Hi Jade Young,
If the amendment to your estimated pay results in a refund an amended tax code will be issued to your employer and once operated any refund due will come back through your wages.
For previous tax year if you do not complete a Self Assessment HMRC will automatically review the tax year after the tax year end and if a refund is due we will issue a tax calculation to you.
If you have a
Personal tax account: sign in or set up once the calculation issued the details will also be shown online.
Thank you.