You could build a frame out of pipe or square tubing, notching around the ropes hinges and any thing else that needs it. Cut the expanded metal to fit the frame and weld them together. Then make shield mounts that bolt to the canopy mount u bolts. Hang the shield on when mowing take it off when done.
This is sort of the plan I'm following. Waiting on delivery of some expanded metal and will be getting started at the end of next week. I'll post some pics of the finished product. Got the mower on Thursday and tested it, but put it in the garage until I get the protection screen finished.