The Greek State acknowledged in the beginning of this present month, that the Hellenic Ethnic Religion doesn't attack the Greek Law and Order, does not offend the Greek morals and doesn't proselytise. Further the Hellenic Ethnic Religion as an acknowledged one, has the same duties as the prevailing Eastern Orthodox Christian Church and is under the same supervision.
So now they may have a temple in a private place and it will be protected by the State.
The Greek State is not very generous with this kind of recognition and the religions that benefitted until now from this law were following five: Judaism, Islam, Buddhism, Hinduism and Baha'i Faith. The Hellenic Ethnic Religion is the sixth one. The Christian denominations are many.
Twenty years ago, when it was permitted for individuals to believe whatever they liked, groups had to ask the local Eastern Orthodox Christian Archbishop for permission, which of course he never granted unless it was possible the refusal might cause a worldwide sensation. After some time it was abandoned, but religions had to have sacred scripture, dogma and hierarchy. So some Hellenic groups had to claim the whole ancient Greek literature as holy scripture, some philosophical books as dogma and titles such as president, secretary and treasurer as sacerdotal titles. Which it didn't help as the Greek State refused to award this recognition. And one day it did. Now it is time to go to the next step. Get recognition as a religious body. Last time the court rejected the name, but now having this smaller recognition might help. Maybe another twenty years will be needed.
Wiki catalogue of religions and denominations in Greek