First you need to get the VIN
Why not send a message to The 'Porsche Pilgrimage' guy Chris Rusby and find out about if he has any contacts in Greece who could help. I believe he saw a car advertised on the samba and went to Greece unsure and came back with a 911. (which it turned out needed work)
https://www.youtube.com/watch?v=jQ01j-ASWAM
I believe he is active on DDK or Impact Bumpers but you could probably also connect with him via Youtube.
I think there is a Greek rally team called CS Beetle and they are / were involved with Porsche racing ? They may be able to help or even know the car. Where is the car located presumably in Athens.
The other fact to remember is non payment of taxes in Greece is one of the reasons they have had such serious economic woes. However as the OP said it could also be indicative of bad finances and inability to keep the car maintained.
Good luck !