[British-cars] Seeking a car cover recommendation

[bill_beecher at flash.net]

I am looking for a new car cover for the TR3 this winter that will do a good
job of blocking dampness and dust.  My car sits in a barn and therefore is
not subjected to harsh weather conditions except the magpies and the
occasional roof leak
 
Moss lists five(5) different covers in their catalog, I am thinking maybe
the Mosom Plus(?), there are a zillion listing on eBay, what is the favorite
for indoor storage under dusty conditions and sometimes a leaky roof?
 
TIA,
Bill