A warm welcome to the Community, rosie81headland-.
While we're unable to recommend whether you claim the car repairs as expenses or mileage, I'd suggest consulting with your tax adviser. They'd be able to give you advice on how to report these expenses and answer any tax-related questions.
In the meantime, you might find this article interesting: About car, van, and travel expenses. This will provide you more details about the simplified expenses method in QuickBooks Self-Employed as well as tips to manage your non-business driving fines or travel between home and work.
Additionally, you can take a look at the following write-up: Mileage in QuickBooks Self-Employed. On the same link, you'll find articles related to your concerns as well as steps to resolve tracking issues.
Keep in touch if you need any more assistance with this or there's something else I can do for you. I'm always here to support and provide additional guidance. Have a good day and keep safe.
