Thanks to everyone for your replies. I had to spend overnight in Dublin the night before my flight last Sunday and at 4am Monday morning got a call from my wife telling me, "you forgot your passport!" It was total panic then as I had to fly out at about 8am. Impossible to get back home and back to Dublin in time. I phoned the airport and Malev and was told no, I had to have my passport (just as I thought but when you're desperate you'll phone anyway)
So, I haven't been able to get to Serbia. My wife told me everything happens for a reason, true, the reason being I forgot my f*cking passpor