In September 2016 Ebay seller 515george from Athens in Greece was selling these Custom Greek license plates. What they are is illegal aftermarket plates with a sticker instead of the official embossed seal. He does say lower down in the adverts they are not official but less experienced buyers might not notice.
These plates are illegal in Greece and would never pass a technical inspection so he must have put the technical inspection stickers on himself.
The dies are completely wrong and this is nothing like a genuine, official Greek plate that always have an embossed seal.
Always check if you are not sure if a plate looks right. These do not and they are very expensive for what they are. Genuine Greek plates are available on Ebay fairly regularly at cheaper prices usually.