There are numerous yards in Greece where you can leave your boat safely ashore and get work done over the winter.
Having sailed from the UK to Greece we have now been there for several years.
Greek winters can be very harsh and windy.
There are three yards in the Ionian
worth considering, one in Corfu and two in Preveza. Flights early season to return can be difficult.
The Agean side has quite a nunber and flights to Athens and public transport\ferrys are good all year round.
If you arrive in time talk to fellow yachties and you will get lots of do and dont do advice