H. I want to know how to list a payment received for goods sold to a customer in Brussels and need to add this information to BOX 8. Can anyone help me with this please?

Hello there, Tonylaird1960.

The net sale will show in Box 8 once you choose 0.0% ECG. Let's make sure you choose this VAT code in those transactions. Check this article as your reference: Common VAT Codes. 

Refer to my screenshot below.

To know the list of payment received by a specific customer, you can pull up the Transaction List by Customer report, then customise it to show the needed information. Here's how:

1. Click Reports.
2. Enter Transaction List by Customer in the Find report by name field.
3. Click Customise, then choose Filter.
4. Click the Transaction Type drop-down arrow, then choose Payment.
5. Click the Customer drop-down arrow, then choose the specific customer.
6. Click Run report.

You can refer to my screenshot. 

If you have more questions, please don't hesitate to let us know. Have a good day!