Rental income via tax code

Good morning, For 22-23 my tax code was adjusted so rental income would be taken monthly from my salary, as I thought I'd be earning below 2.5K from rental income. However, it seems I actually earned 1K more than expected...taking me to 3.5K. So I plan to complete a tax return. My question...Do i just file a tax return for the 1K earned (as I have already paid tax on the other 2.5k via tax code) or do I need to pay tax on the full amount and then somehow try to to recoup the tax already paid?? Thanks for your time.

Hi markyB81
You will declare the total income received.
Having a deduction in your tax code will just reduce the final tax due.
Thank you.