Cheers @Andy & @Patrick
Hi Fred,
I haven't performed an extensive check, but the SEO Spider crawls around 35 URLs with /pi/ in the string, which is presumably not all the products on the site
Patrick actually mentions the issue in one of his points above. Essentially it looks like the site uses JavaScript on category pages for products, example - http://www.netspiren.dk/pl/Helse-Homøopati-Allergica-Ron-serien_58721.aspx
If you disable JS in your browser, you'll see a blank page where the products were. Our tool doesn't execute JS, although Google is much smarter and often can.
However, I'll leave you to verify that -
Hope that helps!
Cheers
Dan