Is there a Customer detailed balance report that lists the VAT element in a separate column?

Hi there, @claire-mignot-on.

You can run the Transaction Detail by Account report it includes the vat element in a different column. Let me show you how: 

1. On the left panel, click Reports.
2. Search for the Transaction Detail by Account report in the search box.
3. Tap the Customize button.
4. Click Rows/Columns.
5. Select Customer in the drop-down under Group by.
6. Put a check mark in the box beside the VAT code.
7. Hit Run report.

For additional resources, here's an article about customizing reports in QuickBooks Online.

You can memorise your report to save its current customization settings.

Also, I'm adding our website it provides tips on how to manage your account and help you with your future task in QuickBooks.

Please know that I'll be right here to help you if you have any other questions about running reports in QBO. I'll be here to lend a hand. Keep safe always.