I think Adi kiddel fished in Holland close to the German border for Barbel, you might be able to divert a bit on your journey out.Also John Bailey caught Barbel close to the German border in the czech republic,and there are some fantastic rivers in Austria (on youtube feeding Rainbows and Barbel underwater by a diver).The book you want to look up is a book by Tony davies patrick,'Big fish in foreign waters' ,you can pick up a copy cheaply and it covers countries and rivers in Europe, in good detail,with quite a lot of Barbel rivers mentioned.Tight lines for your trip,its just a matter of finding out the permissions required.