Use this as leverage. State that the bones will only be returned when four conditions are met.
First, the Orthodox Church is given the authority and funds to rebuild the church and provide for their own security including armed guards.
Second, the Turkish government recognizes the location as a historical religious site in law and by treaty with Italy.
Third, the Orthodox Church is allowed to freely practice their faith without interference at the location and is so recognized by Turkish law.
And fourth, the Orthodox Church believes conditions one through three have been met and formally request transfer of the relics.
Good points all. This will show how serious they are. Historically the cult hasn’t been too respectful of any other religion’s artifacts, traditions and beliefs, although they’re the first ones to scream discrimination.
And that the Agia Sophia is returned to the Orthodox Church...
Fifth condition: When Hagia Sophia is a Christian church again, and St. Nicholas’ relics can be enshrined there.