I thought that a VAT registration number was simply the company registration number with "IE" prepended? If it is then you can look up company registration numbers on the [broken link removed].
Not necessarily Clubman. Company reg numbers are 6 digits where VAT numbers are 7 digits plus 1 letter. There does not necessarily have to be a link between them. For Example: CRo number 223350, VAT number might be something like IE6223350B
Yes, there is a site where u enter companys name or CRO number and it will tell u whether that co is VAT reg and give u the number.... sorry I cant remember link, but try Google
Try this and what you will be able to do is put in a VAT Number to see if it is valid and you get the name and address of the Registered Person. No result means you dont have a valid VAT Number