Going back to PAYE

Hi, I registered for self assessment a few months ago, as I started a self employed role. I have a UTR. This role has now come to an end. I have now gone back to PAYE employment. I am not sure what I need to do next. I have been sent a Simple Tax Calculation for 2023-2024 where I owe a few hundred pounds in under paid tax from my last PAYE role. Do I pay that or should my new employer wait for a tax code that will take this into account? Do I cancel my self assessment i.e tell HMRC that I no longer wish to be self employed/self assessment? If I do that, how do I pay tax on earning that I earned for a few months this year whilst self employed? Or do I do a voluntary tax return on this years self employed earnings first? Sorry but I am unsure of the correct order of procedure. Appreciate help please. Thank you.

Can anyone help with this please?

Hi,
We would need to check if the underpayment is being collected in your tax code. As we will need to access your record to check this, please contact our Income Tax team.
Income Tax: general enquiries
If you no longer meet the criteria for Self Assessment then, yes, you can send a submission to update this. You can check if you still meet the criteria and send the submission here:
Check if you need to send a Self Assessment tax return
If your self employment ceased in the current 2024 to 2025 tax year, then you will be sent a notice to file your tax return after the tax year end, 5 April 2025. 
Thank you.