The island of Drevnik is located in the Adriatic Sea, west of Split Airport, Croatia. Denis Kosor, Head of the ATC unit for the Split region was zo kind to confirm my reception report of NDB DVN on 418 kHz.
Croatian Airspace is divided over 6 Regional ATC centres, part of Croatia Control. I have had some success in getting QSLs from the Regional Centres. Mr. Gadzic from the Osijek Regional centre was so kind to return a QSL for NDB CE-372 (Osijek/Cepin) and NDB OSJ-422 (Osijek Airport).
For who is interested, attached find some details about the Navaids at Osijek Airport.