Espaces do have a tendancy to leak from the join where the roof attaches to the windscreen apperture, If you are brave and know it to be leaking from the top of the screen , peel back the rubber trims that are double sided taped into position , completely fill the gap between the roof and the screen with poly eurethane, then stick the trims back into position ,
Before you do that though, have you had a screen fitted?? if you have take it back and let them sort it , failing that if you do not want to tackle it yourself a windscreen company will charge you about �35 inc vat to do as i describe above . Or if you speak nicely , you may get it done for nothing!