Just one word of warning for anyone with a protec cover.
We took ours off in February on a mild day so that we could open windows and ventilate the van, we were surprised to see quite a lot of standing water on the roof and contacted protec for advice.
The advice was that the cover was probably dirty and that it could be compromising its breathability. Rubbish we thought and told them so, they agreed to test the cover back at their workshop and it failed miserably. They blamed it on a defective batch of fabric from their suppliers and replaced the roof section. All seems okay now, the cover was only a year old so its not like its old and deteriorating so I suggest checking after rainfall and make sure you haven't the same issues as we've had. I think trapped water under a cover is worse than not having a cover on at all so please check.