Hello, ZGB432
Well, your procedure is quite simple.
You need to go to appropriate police station. Since you're in Zagreb, from what I can see, you need to go to Heinzelova 98, room 39.
I will sum it up for you:
You can get HR driving license without any problems. You need:
1.) UK driving license
2.) one photo 30x35 mm
3.) 35,00 kn administrative tax stamps (you can buy at newsstand inside Heinzlova police station)
4.) proof that you paid 151,00 kn (200,00 for urgent procedure, finished in 2 days) for driving license issuing costs, use IBAN for state budget:Â HR1210010051863000160, model HR65, call to number (poziv na broj) 7005-477-OIB (where OIB is your OIB (you can also buy bank transfer order already filled in with all the data at same news stand in Heinzlova PS and pay at post office inside PS).
5.) proof of identity and some document that proves you've got you're residence is in Croatia or that you've been here for at least 6 months.
If there is no date of issuing on UK license, you will also need some proof when it was issued.
That's about it.
Just take some money, go to newsstand in Heinzlova, tell them what do you want, you will get paperwork, you fill it in, pay at post office, take that to room 39 and you're done.
You can pick your license in 2 days if you go with urgent procedure or withing 30 days if you with regular (you get temporary certificate valid for 30 days you will use to drive in the meantime).
I hope this helps.
Oh, I'm pretty sure you will actually have to deposit UK driving license with them since you can have only one valid license.