In reply to Removed User:
I could just use glass, and then thought to google which is greener, and it turns out that polycarbonate sheeting is greener than glass to produce, and is more efficient thermally too, so I've ordered a small piece of that to compare with the glass. If it's clearly different and I don't like it's appearance enough to order some glass, my environmental footprint has been small for the past 12-13 years.
It being lighter may help with any DIY in the future, when positioning it during any repainting and things...
Post edited at 19:00