Ancient Greek Art stamps on Olympic Torch Flight

Olympic Torch Flight Cover from Athens to Australia canceled on November 2nd 1956.

The cover has two stamps :

Voyage of Dionyssos

                                                          

Bust of Homer

                                     
Both were issued on July 10th 1955 and are part of the Series of Ancient Greek Art.
 
Here are the stamps from the cover and the postmark in detail which is nice as such but misses a bit of ink.