Thanks for the suggestion, Ben. When I bought them a few weeks back I explored Iittala, Nuutajarvi and Orrefors and, while the former seems the most likely, I couldn't find the exact pattern. A Google search threw up an old eBay photo which looks the same which described them as Iittala but, of course, the listing has long gone so I can't verify whether the seller was simply suggesting it or giving the pattern a firm attribution, unfortunately.