You may be registered as a self-employed Nanny but that doesn’t mean it’s legal. From what you have described you absolutely do not fit the legal criteria for self-employment. The parent is a nurse who works shifts, where you are required to change your hours to cover her shifts. This alone means that you cannot be classed as self employed.
A Nanny can only be self-employed in rare situations - for example does lots of temp positions, sickness cover, works for several families, chooses their own hours when they are available, sets their own hourly rate etc.
Im less worried about paying for trips. More concerned about the following - are you:
- Paid at least minimum wage?
- Getting 5.6 weeks of paid holiday per year?
The average Nanny pay in the UK is £12.21-£15 ph for an unqualified, less experienced Nanny. Then £15-20ph for a more qualified/experienced Nanny. Obviously this will vary a little on the region.
However if for some reason you do qualify for being self-employed (have you checked with HMRC, or just decided yourself?) then you should be setting your own hourly rate, when you are available for work, invoicing her every month for your hours and any additional costs you have accrued. And your hourly rate should be much higher than minimum wage because you need to cover periods of unpaid holiday, sickness, pension, your own admin costs to do your own accounts etc.
Time to sit down and have a very frank conversation with your boss. If they aren’t willing to pay you properly as an employee then you should look for a new job.