Thank you for posting here in the Community, @gjflooring.
When entering an expense that's partially exempted from VAT, you can use two separate lines in QuickBooks Desktop. The first line would be for the vatable amount, and the second one will be the remaining balance.
For future reference, check out the Enter bills article. It provides an overview on how to record payables through the Desktop version.
I want to make sure this is taken care of for you. If you have additional questions or concerns while working in QuickBooks, leave a comment below. I’m here ready to help you.