Sounds like soft top ownership to me. After all, you chose them to be closer to the elements, right?
Conversely, I treated my CS to lovely Luxor indoor car cover from a company called Concours. Really nice material, breathable and fleece lined. The fit is really good too. Think it came top in a recent car cover test by Auto Express. Reasonable price, even compared to similar covers available via the PCGB with discount.
Perhaps a little over the top, but should protect the car from the m-i-l rooting around our garage for her golf clubs. Plus I've saved a few hundred quid by not using a company to store the car this winter.