Hi Mike. Your vehicle expenses may include costs that are not considered necessary or solely for business purposes, which is why they may not allowable.
Disallowable expenses cannot be deducted from your taxable income. On top of that, QuickBooks will classify your vehicle expenses as allowable or disallowable based on the category you choose. To determine whether you can claim VAT, I recommend checking out this article: Allowable and disallowable expenses explained.
You might also find these resources helpful if you wish to learn more about self-employed expenses and organising your transactions in QuickBooks Self-Employed:
If you have any other questions or concerns, please feel free to leave a comment below.