if you cant go for a carcoon then i suggest a proper fitted outdoor cover.. im sure a few have been mentioned here... although most of them cost as much as a carcoon!
I drive the work van on a day to day basis and just use my own car for personal use , which might be every night for a while or might occasionally not turn a wheel for a couple of weeks . Usually , my car is out once or twice a week .
I occasionally use my car for work if the van is being serviced or unavailable for some other reason .
My 300SL has become a garage queen ever since our little boy arrived 3 years ago.
I even made a hardtop hoist so I would be inclined to drive it when the weather got a little colder. Unfortunately that was a waste of time as it rarely gets driven on sunny days let alone cloudy weather so now the hardtop sits above the car almost all the time.
My 320 coupe comes out for shows or occasionally a pleasent jaunt on warmer days, when the windows can be dropped.
Between MOTs March '09 and '10, I only drove is 2,000 miles though
The Audi, on the other hand, completed around 17,000 from Feb '09 to '10 (This was the approximate annual mileage for the Merc, before it's semi-retirement).