Hi, I use a Halfords cover. It seems to be at least as good as much more expensive covers I have used & so far, after 2 years still doing the job. But the car is used virtually every day, which ensures it gets fresh air. The car has been left under it a couple of times for a month with no Ill affects. I live near the sea which is a challenging environment. The only problem I’ve had is the under tank boards rotting. Don’t think that was the cover’s fault.