Unfortunatelly, they are real bunch of idiots in Croatian CAA. Most of them employed without any experience or education in aviation, mostly lawyers, economists, some ex pilots (these are the worst). Now when they grabed some "high positions" over there, they think that they are at the top of the world and hardly can happen that someone succeed to convince them that they are wrong. And the worst thing is that you cannot complain to anyone. The only way is to know specific appendixes, annexes, conventions, laws etc. very, very good. To be veeeery persitent and to show them exactly where in documentation is something written.
Now imagine that you are living in Croatia and flying with their license. An unforgetable experience and never ending story
As Saab340 said, Tivat is an option and is really very near to LDDU, but you should then maybe check if there are some visas required.
Hello from Croatia!