Winter cover for motorhome

Hi all,

Can anyone please give us some advice? 

We have always stored out motorhome under cover during the winter however we have now changed to a bigger model which just won't fit in!

we have been looking at covers and they seem to come in either "water resistant and breathable" or "waterproof".  Does anyone have any advice on what's best, and any recommendations of where to get a good one from??

Thank you for any advice ;)