posted about 3 months ago
As a registered student you are exempt from council tax regardless of work you do on the side.
If you are receiving a stipend for your PhD, that will be tax free and you dont need to declare to anyone.
Your job title, if you need one, is student.
You will have to pay National Insurance on your earnings from payroll work but the uni will sort that out for you. Depending on your tax code you may also be paying tax but in April time you will get that refunded to you by HMRC.