Hi,
Your P45 should show your total taxable gross pay for the tax year to date along with the tax you have paid so far. If you do not think you will be receiving any further taxable income in this tax year, you can complete a P50, which is an application for a tax repayment for 2024 to 2025.
If you are not yet decided,. then once the tax years has ended we automtically review your tax record and if any repayment is due we will advise in writing, usually around May to July. You can see guidance here:
Claim back Income Tax when you've stopped working (P50)
Thank you.