Citroen C3 Pluriel 2005 - sunroof jams over rear windscreen

[horrakapotchkin]

Hi, I have just bought a Pluriel 1.4. The sunroof operates fine until it slides down over the rear windscreen where one side seems to stick causing the roof to jam. I can close it by assisting it on one side with my hand. Does anyone have a schematic diagram or links to a workshop/service manual please? Many thanks