I often get bad condensation on the inside of the windows in the mornings. In bad frosts the whole of screen is covered in ice inside. The car doesn't smell damp and there is no sign of moisture in the carpets. Any ideas?
Check underneath the carpets, any water getting in will settle
On the floor if the car underneath the soundproofing. The surface
Of the carpet will only feel wet when saturated.
Check under carpets as already quite correctly suggested, check for damp pollen filter & stick a dehunmidifier in the car for a few days to dry it out. make sure air con drain is clear incase water tray leaking water into car.
If its the one with the steel folding hood its probably leaking somewhere they generally do in Germany they say you have to take an umberella with you to keep dry when it rains in these kinder wagens