The above statement is incorrect. The Greek government does not call the King Constantine, De Grecia, King Cnstantine has no Greek passport, in fact, the Greek government has no relationship with him, but they does not call him in any way, they are not competent to it. The politicians, some disparagingly call him Glücksburg and others, Ex King , for example Tsipras ,in the airport of Athens he called him, Ex King Constantine.
The general nationality law cannot be applied to the Greek royal family, so, the reside in Greece for a period of time, or assume a surname ... this cannot be applied to members of the Greek Royal Family, Why?because It was made a special law ,1995, whot withdrew their Greek natural nationality, and established special conditions. This law deleted their natural nationality to members of the Royal Family.
Among special conditions: a public resignation to defend monarchical values, it had to be public, they had to publicly swear the Greek constitution ... and others, such as a surname that the socialist government proposed it to be, Glücksburg (it is not surname) .
This law is marked by ideology of the Greek left-wing political parties , (They intended to regard the Republic as State's form of natural of Greece, and the monarchy as a foreign element to the natural State of Greece), in fact, the Greek right was absent from the debate and subsequent vote, considering that the law did not fit into the Greek Constitution, the Constitution, which prevents the withdrawal of the passport to persons born in Greece or on Greek soil.
As I say, the law establishes that even if the King fulfilled those requirements, he would not receive or recover his natural nationality( withdrawaled by this law). He could receive a greek pasport but no his natural nacionality. This is ridiculous, why, because Constantine was born in Greece, did military service and was Head of State ...
King Constantine just hopes that one day the law will be repealed, considering it unjust, he will never renounce his natural nationality, ever.
King Constantine has not refused to accept a surname, on the contrary in 2015, he requested administratively the license to live in Greece, the State lawyer, in the process, opposed it, claiming that the 1995 law also affected to the residence, but the Judge Sentenced:
-That the 1995 law does not affect residence
-That Contantine could be identified in the documents as Ex-King
-That Glücksburg, was not the surname of the Family (It refers to a Resolution of the Council of State of Greece, 1996)
-And that in order to identify him he would need a second name, the Judge, completing the law, recognizing that the family did not have a surname,she(the Judge) offered the King as a second name, the name of his father, Pavlos. King Constantine accepted it.
- In the administrative documents it appears as, Ex King Constantine Pavlos.
This resolution only has administrative effects, but as you can see, the King has not refused to accept a surname,. The general law cannot to be apply to the King Constantine and his family because there is a special law, 1995.
Prince Pavlos and Princess Marie Chantal have British passports and so do their children. Their surname "of Greece", it is in their instagram accounts
Do you have links to any of the laws, judgments, or documents you addressed? 
