I bought a Lidl car cover (medium) for £10 recently. At that price, I didn't expect much, but am pleasantly surprised.
It's polyester and indoors - only, but has an elasticated hem, and fits snugly as if it were tailor made. Perfect for over-wintering your precious 2 !
Cool - i got one from ebay for about £20. Was too surprised at quialty and fit. Great for keeping the car protected over winter.