Mokka leaking coolant

[chan]

Just got the water flange changed and full service on mokka 2016 and once I drive then car,coolant starts leaking out slowly over night . Need advice taken to two mechanics, one says radiator needs replacing. One says they can't see the leak once they took out the water pump. I am confused on what to do 

[Finn]

Not sure if this will help, my meriva 1.4 petrol turbo, had a slow leak and nobody could find it. Took it to a traditional garage and it was the turbo pipes, meriva turbo water cooled.