How can I choose the Supplies location for VAT Return purposes as looks like it is working wrong

Make sure to set up VAT correctly to prevent any issues, accounts337.

QuickBooks Online automatically creates a default VAT code. To do this, you'll have to turn on tax tracking, then set up sales tax. You'll also see the Tax Center with a Tax/GST column on your sales and purchase forms.

You'll want to create additional tax rates if you need to change the default one. Please follow the steps below:

1. In the Tax Centre, use the side arrows to find the tax you want to deactivate.
2. Click on Edit tax in the top right corner
3. Click on Edit rate
4. Under Action, click Edit and then click Make inactive

Since you can't have two rates with the same name, you can rename the deactivated tax rate, then create a new tax rate with the correct name.

Please check this article if you want to enter your VAT Registration Number in QuickBooks: Why Do I See A VAT Charge For My QuickBooks Online Plan?

You can run reports in QuickBooks Online to show different aspects of your business. Please read this article for your reference: Run Reports In QuickBooks Online.

Leave a comment below if there's anything else you need. I'd be happy to help.