Tissier (7th dan) and Gouttard (6th dan) sensei are both direct students of Yamaguchi; this means France is probably your best bet to find what you're looking for.
They are probably the most renowned sensei in in France and organize seminars around western Europe (France, Germany, Italy and Switzerland).
In Italy an entire federation (ADO - UISP) has the Tissier school as technical/didactical referee; you can find dozens of dojo around, their best instructors (V dan) are located in Torino and Roma.
For more detailed infos, try:
(ADO UISP italian dojos)
Unfortunately I don't know the corresponding organisation name in other european countries (probably the FFAAA in France), but you can easily find it out with google looking around for "Christian Tissier"... he's pretty famous here in Europe (and one of the few non-japanese aikikai shihan around here).
Hope this may help you, have a nice stay here in Europe.