I've replicated your concern, Steven_ZA. 

You're unable to filter the report by a specific account. The transaction will automatically be under the specific block they're categorized, depending on the tax you've selected. I'll add this article to help you learn more about the report: VAT Detail Report.

You'll want to pull up the Transaction Detail by Account report instead. Then, customize it to the specific account and add the VAT amount. 

If there's anything else that you need, feel free to reach out to us. We'll be around to help you. Take care!