You're correct of course Richard in any normal situation, the idea of the garage cover is to offer some protection as my wife and folks stumble through the garage looking for tools in my absence. I had a beautiful Pagoda and DB7 VV both with scuffs so I cover everything in layers now when I'm away.
The MMC cover just seems to offer a good 'fit' but that is in their photo so advice from an owner would be good - very much appreciate you comments.