I have a Dometic Flytex FT200 fitted to my PVC door. Problem is the control cord that’s threaded through the mesh has snapped. Seems to me it should be a DIY repair using a darning needle and replacement cord costing pennies rather than junk it and replace at £350! The frame looks like it will come out easy enough, but I can’t figure out the configuration of the cords. There appears to be two adjustable cords secured at the top & bottom corners of the frame leading edge. Has anybody tackled this job? Advice and ideally pictures most welcome.