Nigel - Before the brexiteers ruined everything, I'd have suggested this:
Car-Cover Car-Cover Satin Black für Chevrolet Corvette C5 online entdecken ✔ große Auswahl hochwertiger Ware ✔ TOP Preise ✔ Schneller Versand ➤ jetzt bestel
www.kfz-schutzdecken.de
We have these covers for the Corvette and the "Roller Skate - beautifully made in lovely soft material and a nice fit, even though it's not a "tight-fitted" type and comes with a nice bag to put it in when not in use.
The company were excellent to deal with and delivery was fast and not expensive. We looked a a LOT of covers before we bought this and have yet to see a nicer one at anywhere near the price.
BUT, I don't know how importing one from Germany will work now for you, but it may be worth asking them.