Hi, does anyone have a recommendation or just some words of wisdom for which supplier/service to use for checking a VAT no.?
Have a look at the EU Commisions own SOAP service which you can find here: http://ec.europa.eu/taxation_customs/vies/checkVatService.wsdl
Nephics has a Json API I've used in some projects. It's a proxy for the EU commisions VIES service but also retries requests when there's no response and does some caching to speed things up a bit. And personally I prefer Json over SOAP... Look here: http://nephics.com/euvat