Self Employment and PAYE Employment - Tax Deduction Questions

Hi there, I hope you are well. I'm currently a self employed graphic designer and also an employee for a local newsagent/convenience store. At the end of each tax year I usually send both my self employed earnings/spreadsheets to my accountant, along with my employment payslips. He calculates how much tax to pay and I pay it through the HMRC portal. When this current tax year started, my employer started deducting tax directly from my PAYE wages - using the tax code 1257L. I emailed their HR department but they said that they cannot change anything, and I would need to contact HMRC. This is strange, because the same event happened last year (23-24 tax year), but after a few months, the employer refunded me the tax I had paid - and I set it aside for when I speak with my accountant. But this year, they continue to deduct tax. Please could someone explain why this happens? I would still prefer to deal with my accountant and pay tax through the HMRC portal after my self assessment, instead of directly through PAYE. What could I do about it? Thanks!

Hi
Unfortunately, we are unable to provide specific advice tailored to individual circumstances on this forum nor access your records to check tax codes or deductions. 
You can contact our helpline:
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On this page you will see a link to personal tax account: sign in or set up which may be the quickest way to review information relating to tax codes and change them.
Thank you