Renault Traffic 04 CD 100 Lost clutch pressure?

The vehicle has sat still for a couple of months and when pressed the clutch pedal "sprung " to the floor. It takes its fluid from the brake reservoire and is not low. However there must be a loss of fluid I imagine at either master or slave cyl. Both are odd...master seems to be part of the pedal and slave is more like a thrust bearing inside the bell housing! Great! Typical French design. Has anyone had any experience with this problem. Could I be lucky and find it has just got a master cylinder problem? No bleed nipple is evident?? Help much appreciated.