foam insulation tubes for pipes (West Byfleet, Surrey KT14)

Please see photo. I wonder please if anyone has some foam tubes as used to lag and insulate central heating copper pipes they’re no longer in need of. I’m using a metal trellis with many slats, on which I’m trailing à vey vigorous vegetable plants that has vines and tendrils. This trellis has many slats that gets very hot from the sun, causing the vines to scorch. The measurements of the foam tube size that fits around these slats are; the actual hole 25mm, the thickness from the hole outside is 9mm, but I don’t mind if this outer measurement is fatter. I’m in need of quite a bit. Thanks very much. Valerie