Reclaiming tax on returned overpayments of ESA

Hi, wondering if anyone can help? I am trying to complete Self Assessment Tax Return but don't know where to put the following info: In Tax Year ending 5.4.23 I was overpaid ESA (contribution-based). This ESA was listed as taxable income on my P60U, and on my Tax Return for that year. I recently found out that I had been overpaid by about £5K. I returned this overpayment on 25.4.24. As I will have already paid tax on income that I have returned, I am wanting to reclaim this tax. I spoke to an HMRC agent, who didn't understand and simply told me 'ESA benefits are not taxed'. This is incorrect, as my ESA was contribution-based (which is taxed) rather than income-based (which is not taxed). I have tried putting a negative amount in on the 'Benefits' section of the Tax Return, but this is disallowed. Help! Any thoughts?

Hi,

Contributions based ESA is taxable income but not taxed when it is paid to you. If the figure entered on your 2022 to 2023 tax return is more than you received then you can amend the tax return to show the correct amount.

Self Assessment tax returns

Thank you.