One of the best materials for the wicks is made from the RubberMaid MicroFiber Webfoot mop head. These are made in US and are nearly impossible to find in Europe.
After using nearly 2 weeks on finding a source for these here in Europe, I stumbled on the following address:
Lichfield, WS13 8SS
One could call +44 01543 447 000 and ask for the "Rubbermaid Commercial" department.
I've got ahold of a guy from Sweden, Joacim T. He's the representative of Rubbermaid products for the Nordics (and I'm from Denmark which is the part of the Nordic countries). You might want to talk to someone who's a representative for your region in Europe.