6SN7 tubes in Europe ???

Here is a place that explains tube basics in both English and german.
http://www.radau5.ch/basics_1.html

Here is a place in Switzerland that has 6SN7 tubes for sale.
http://www.chemie.unibas.ch/~holder/LAMP/tubelist.php

Here is a place in Germany that has the tubes you want.
http://members.aol.com/jmelectr/

And here is World Wide Tube Portal where you may find dozens more:
http://www.worldtubeaudio.com/directory/categories/kategorie_11.htm

Good luck !