When selling products that are 20% VAT in the UK the product tax rule is left blank so when selling to an EU country the customer tax rule is applied (EC Zero Rated).
When a product is zero rated then 0% VAT needs to be set up as the product tax rule, otherwise 20% would be applied when selling to customers in the UK.
When selling these zero rated products to the EU, the VAT rule should be EC Zero Rated so the correct figures show in the correct boxes on VAT returns, but as 0% VAT is set up at the product level, this is what's used.
It would be useful to be able to override the product rule when selling to other tax zones, because at the moment, each zero rated product on the order would need to be changed manually for 0% VAT(UK tax rule) to EC Zero Rated.
There could be an option in the customer record to override product rule, or a button on the order to do this.