Looks like there are a few on eBay - no SEAT ones, but then it's only a
sticker...
If you have one and the insulation material has perished, you can get hold of sticky-backed material on eBay too - I thought I'd need super thick stuff, but it's not that important - and mine came unstuck fairly quickly too, so if I do it again I'll do it with thinner material that's easier to manipulate.
If you haven't got one, there are plenty of people who will say you don't really need one. I just think it makes the engine look more presentable.