As a private person you do not need to fill in the VAT number when ordering any item on Ellié Computing website. VAT numbers are assigned to businesses and not countries. Business customers can register their VAT number to bypass the additional VAT charge in the order. By doing this they are stating that they will settle the VAT through their company instead of paying it for each item that they purchase.
This is different for non-EU based retailers, who have to apply the VAT rate of the EU country where the customer is located.
Please note also that sales to our customers outside of the EU are exempt from VAT.