Tax Refund and Deductions: UK Resident Working Abroad with a Part-Time Job

I am a UK-settled resident (ILR) who moved abroad in August this year for work, but I plan to return to the UK within the next three years. Currently, I have a part-time remote job in the UK, which I started in March. My gross salary is £500 per month, and my employer is deducting £100 as tax (under tax code BR), with no National Insurance contributions. I believe I’m not liable to pay tax on this income, but it’s being deducted. Additionally, I resigned from my full-time UK job in August, and it seems I (or my previous employer) overpaid tax during my employment. Could you please guide me on how to address these issues? Specifically: How to reclaim the overpaid tax from my full-time job? How to ensure my part-time employer stops deducting the £100 tax if I’m not supposed to pay it? How can I make NI contributions from abroad and what type of contribution? Any advice would be greatly appreciated!

Hi,
You should complete the P85, we can then review both of these issues.
 Get your Income Tax right if you're leaving the UK (P85).
Thank you.