Lumpy engine idling, petrol 1.2 DOHC 16valve Chevrolet Aveo?

hello just took delivery of a brand new Aveo petrol model 1.2 DOHC 16valve 60 miles on the clock and at idling of 500rpm it dont seem to be idling that smoothly at normal engine temperature. If I crank up the revs to 1000rpm the engine to's and fro's from 1000 to 1500rpm on its own. when on 500rpm it stays still there at 500rpm but sort of vibrates rather than idling smoothly. Do you reckon should take it back to dealers, or should I wait until engin has 'run in' a bit more seeing as its new or maybe the ECU is working in 'safe mode' and after amount of time will 'learn' and then it will idle better? - what do you reckon? its not bad but its a bit of a niggle especially on a brand new car like this.