Dinx, I'm not sure about your parking/storage situation, but if a garage is out of question, you should look at a semi-permanent storage solution like a carcoon.
Basically, you drive you car into these things and zip them up. Plug it in and it inflates. It has a fan in it at each end, so that its ventialted, so it won't 'sweat' and rust your p&j.
I would then lookinng at covering the carcoon itself with some tarpaurlin or similar so that its not visible . It really boils down to what space you have available.
If all of this is out of the question and you have to go for a simple car cover, then go for the best you can afford, made out of a mutli-layer breathable construction. Never put the car undercover when its wet, and air it out often.
As for insurance, keep the fully-comp no claims policy running on the cab, get yourself a thir-party only second policy on your run about. This will allow you to build two lots of no claims bonus, with the cheapest possible policy.
