We've build arbinon.com to support all Amazon marketplaces.
However, we have only been working with clients that have access to the North American marketplaces of Amazon.com, Amazon.ca, and Amazon.com.mx.
We have not developed for, nor tested features and functionality unique to marketplaces outside North America at this time, (ie. UK VAT & post-BREXIT changes, EU VAT and compliance, points in Japan, etc.).
Expanding for those markets is on our development roadmap.