I'm here to assist you with changing the VAT number on your invoice, Tracey.

It can be that VAT was set up accidentally. We can check by clicking VAT on your left side panel. And then, since you're not VAT registered, we can set the default rate selection to Out of Scope of Tax or No VAT on your invoice.  Here's how:

1. Go to the invoice you want to change.
2. Under VAT, select the dropdown.
3. Click Out Of Scope.
4. Hit Save and close.

If the VAT was set up, we can change the default rate to out of scope to ensure your invoices will not use VAT rates in the future. Follow these steps:

1. Go to the Gear icon.
2. Select Account and Settings, and then click Advanced.
3. Under Accounting, click the pencil icon and choose the Default tax rate dropdown.
4. Select Out of Scope of Tax.
5. Hit Save and then Done.

However, if you mean changing the VAT rate, check out this article to learn more: Edit VAT rate in QuickBooks Online.

Moreover, you can visit the tax centre to record, adjust and delete VAT payments.

If you still have questions about your VAT, the Community is here 24/7 to assist you. Have a wonderful day ahead, and take care always.