Couldn't stay at the Eleni this year as it is only available through Kosmar and all rooms were taken on the dates we wanted. However I visited Kostas at his new restaurant Andromeda which is excellent. The food is in a different class to the usual fare. Cannot fault the place and very reasonable too.
We spoke to Kostas about availability at the Eleni. He told me that his Kosmar allocation was sold out very quickly. Unfortuantely his other rooms are often empty as no other tour operator will take an option on them. He suggested flight only and book rooms direct with him via his webiste.
Try and make an effort to visit the restaurant at least once during your visit. The guy is making a real effort and deserves support.