At the moment, VAT rates default to the rate set for each item.
Unfortunately, since July 2021, this is no longer applicable for sales to an EU country, where the VAT rate is linked to the country where the buyer is based.
Despite suggesting changes to this months ago, nothing has changed in Kashflow and I find that for EU customers, I have to change the VAT rate on every invoice where the customer is based in the EU.
This is a real issue as it could lead to items being included incorrectly on the UK VAT return (or an EU VAT return where the seller is registered for union OSS and also has to charge destination VAT)