I would agree with SB's routing. However, the Corsica route is a long over-water crossing, out of radio contact at 1000ft below the stupid Italian Class A airspace extending many miles offshore.
10hrs endurance - sounds like a DA40/DA42?? They can do the Alps at FL160 easy, with oxygen of course. Direct UK to say Trieste, then one leg to Corfu or even the destination. Greece is quite limited in airfields with Customs and Avgas.
VFR past Albania is OK. Montenegro is the pain; Albania (LATI) is extremely nice; I've been past VFR and landed there (IFR) a couple of months ago (Euro 230!).
You have a PM, Stik.