For anyone that needs to get an international drivers licence while you're in Korea......
You dont need to travel up to the driving centre at Jindong (near Masan) anymore.
You can go to the Police station in Okpo (near the fire station) and they will issue it in there. Apparently only started doing this recently.
Got one today, very straight forward. Just bring a passport sized photo, your passport, alien card, Korean driving licence and a credit card (not sure if they'll accept cash, they just asked me for a credit card).
There's a form to fill in with basic details (name, address, signature etc.).
Whole process took around 15mins.
Total cost was 8,500Won.