Having a VAT number (in the Netherlands) is no problem. Just visit the KvK (Chamber of commerce), sign up as a one-man business and you are good to go.
A business bank account is not even required. Just be sure you keep track of what you do and what you sell, thus you will need some kind of administration. And keep the VAT separate and eventually pay your taxes
If you need help in any kind, I'm here to help you out.
Product looks great, I don't drive a Dex, but to me it looks like a nice addition. I normally drill my wing mounts as well, but without enough material around the screws they snap easier.