Are you coming for holidays?
6-7 of october we have the HAA National Instructors Seminar
its in larisa (central greece) its easy for you to get there
and a lot near to many interesting staff you would like to see in greece
However what i recommend is Fukushinkan Dojo, Athens Run by Koliopoulos Sensei 5 Dan Aikikai.
You would be impressed he is the very best