Their website states they take international orders but it sounds like it has to be in stock stuff and takes a day or two to ship. I don't know about duties with DFD.
I do know that if you're ordering a lot of parts they often are out of stock on items and there seems to be a supply chain shortage lately which worsens that issue. It can be frustrating when you're trying to piece a project together and a couple of the parts aren't in stock.
If they have the stock you need, they should be able to handle it. I just got a package of tension rods from them a few weeks ago. I’m in the states but no issues whatsoever and a friendly Thank You card came with it.