losing anti freeze coolant

Hi everyone losing anti freeze coolant on my symbol no signs of leaks anywhere. any suggestions would be appreciated. 

My Peugeot very slowly lost coolant from new, as did my work colleagues. We both had a leak in the same place which was a plastic tee piece which can be accessed/located between the radiator  and the engine if you look from underneath the front bumper in the centre of the vehicle. Had to replace to hose clip with a jubilee clip.