Hi Lumix & Monika,
My Engine Hood Insulator is also a little tatty.
I have been considering making one from a product such as Armaflex FR.
I tried to attach a brochure but it wouldn't. Armaflex is a black synthetic foam rubber type insulation material, commonly seen in tubular form for insulating refrigeration pipework. It is also seen as protective padding on roof-racks.
It is available in 1.0 m x 1.5 m sheets, & 6mm & 9 mm thickness.
Does anyone have any experience or comments ?