How do I account for 5% VAT rate (say on fuel) or variable rates of VAT when I recharge items such as subsistence?

Great day, @david78.

Thanks for posting your concern here in the Community.

The VAT codes listed in QuickBooks is defaulted based on HMRC's tax code system. You can go to the Taxes page on the left menu to add or edit tax rates. You can select the Custom tax since you're accounting for fuel tax. Here's how:

Adding custom tax

1. Click on Taxes on the left menu.
2. Click Add tax.
3. Select the Custom tax.
4. Create a Tax name for your custom tax rate, and enter a few details about how you track it.
5. Choose and check the box if the tax is collected on sales or collected on purchases.
6. Enter the Sales rate for tax collected on sales and the Purchase rate for collected on purchases.
7. Click Save.

Editing your VAT Settings, Codes, and Rates

1. Click on Taxes on the left menu.
2. Click the drop-down arrow next to Edit VAT.
3. Choose Edit Settings or Edit Rates.

The 5% VAT rate will then appear in the drop-down selection for VAT so you'll be able to account your fuel expenses. 

If you have not set up your VAT yet, please refer to this help article: Set Up and Edit VAT Settings, VAT Codes, and VAT Rates. It will guide you through managing your VAT.  It also contains a link to check whether your business is eligible to follow the rules for Making Tax Digital (MTD) for VAT.

Feel free to post again if there's anything else you need. We're always glad to help you. Have a great day!