clear plastic/corrugated sheeting (St leonards TN38)

Clear Poly carbonate sheet or clear plastic corrugated sheet. Enough to cover a total of 2.5 square meters.
Last bit required to finish an outbuilding made of wood from skips and fly tipped plywood.
Just require 2x (right angled) triangles of something clear measuring 1.2 base by 1.2 upright to finish. Have you something lurking in your garden/shed??
Many thanks 🤓