I can understand why that would be confusing for your accountant. When you say you are VAT registered, did you set up this additional tax directly on your eBay listings or on your PayPal account? If you set this up on eBay, you will not be able to see the distinction on your PayPal account for this charge. If you set this up directly on PayPal, you'd be able to download your history and customize the download to add this section if it isn't pre-selected. You'd go to your Reports section, Activity Download, and then select 'Customize report fields'.
If you need help setting up VAT on PayPal, you're able to set this up in your Selling/Payment Preferences.