Good morning Charlie.
If you look on the Uk Referendom site you will find a posting by SPARDO.
He is a brit living in France who for years moves dogs about all over the continent, have a look at his site.
Due to insurance issues arround 1999- 2002 in old Yugo I did a few Fast ferries from Ancona to Igoumenitsa, Kozani, Bitola, up to Skopje.
That was a unit and fridge so a van would be a lot cheaper and boats have dog cages on deck, maybe worth checking out eh ! Harvey