I sell on eBay and I sell to everywhere. If you are in the UK or your eBay account is blocking you, simply contact the seller and ask to buy via Paypal only. eBay technically says this is not allowed but eBay owns Paypal so they still get paid either way and do not really check or care. Of course you should really check the seller`s feedback before you try this, but you more likely have already if you are going to buy an expensive sword. Also, you still get the protection that Paypal gives you.
I have also had many Aussie customers and there has never been any problem with customs. I have never shipped a double edged blade to Aus. though so maybe that is why.
For France, it is very important that a very well written and clear invoice be included with the sword. This seems to be true with most of Europe. The invoice needs to clearly state the age of the sword to prove its age. This is mostly for custom taxes. In many European countries, such as Germany, the import tax is greatly reduced if the item is an antique. I`ve been told it drops from 16% to 6% in Germany!