Roof Window on Wooden Conservatory?

I need to replace the felting that covers the top end of the roof window. Trouble is apart from removing the lower polycarbonate panel end caps and "U" shaped panel end caps it seems the the panels are also held down on their long sides (guttering to roof top) by long wooden strips. When I went to remove the screws bottom to top the screw heads appear to be damaged like someone has used a wrong size Phillips screwdriver?

My question is how can I get to the ridge end of the roof to replace the felting without risking the possibility of the roof structure being damaged?