Hello there, @omega2011.
Thanks for posting here in the Community. I understand that you'd want to keep the VAT off in the VAT return.
When you choose a No VAT code for your transactions, the amount of the transaction will appear in the report but with no tax amount.
Since this isn't a purchase transaction and doesn't come into the 0% category, I'd recommend you deselect the vat code, or you may not select any vat codes for this transaction so it won't appear in the VAT returns.
To learn more about Vat codes and when to choose them, check out these articles for future reference:
Let me know if you have additional questions about VAT returns, @omega2011. I'm always around here to help.