Plexiglass (Llanberis LL55)

I'm looking for one or more large(ish) clear sheets of plexiglass, either acrylic/perspex or polycarbonate, preferably flat but would consider single corrugated polycarbonate or double walled flat type roofing sheet(s). Clear sheets used for Covid protection in shops etc might do if no longer needed and if large enough. MJN