I currently have a small job which pays about £5000 per year. I am on the payroll for this, get proper payslips etc.
My neighbour is a self-employed cleaner and has increasing demand. She's offered me 5 hours per week cash in hand - so I would invoice her at the end of each month. This could work out at about £3500 per year, taking my total earnings to £8000-£9000.
Since this is clearly below the tax threshold, would it be ok to do this without involving HMRC or registering anywhere? I just don't see the need if I wouldn't be paying tax anyway. I'm not entitled to any benefits either (due to my savings + DH's income) so that's not a factor.
Any advice much appreciated!