We bought a new
cheap caravan cover from ebay, (similar to the one in the link) and we think it's great. It's not a ProTec, but is a breathable fabric, with a very soft feel to the interior face of the fabric. It really keeps the van clean and dry, and is easy to fit. It has zips on the corners and each of us uses a sweeping brush in the lead corners to lift it up, over the roof vents, and once past there we can just pull it into place. We find it easier to fit starting at the front rather than the back. It hasn't scratched the caravan or the windows, as I posted in the thread mentioned above which complained about a Protec cover making marks on the van. Our storage site is in an exposed situation, on the top of a very windy hill, so the cover gets plenty of work, but it keeps off the dust, the black streaks, and the rain and it's a joy to unwrap when we go away, seeing the van just as pristine as we left it. It also protects the paintwork from the sun, keeping the shine longer once it's polished.
It doesn't have a 'door panel' but we can manage to get inside (just) by opening one corner zip and slackening the ties, so we don't have to take the cover off all the time. I think, apart from the caravan itself, it's one of the best things we've bought!
I know lots of members disagree with the use of covers, but we've had lots of our nieghbours on the storage site asking what we thought of ours. When we first put our van on the storage site, there were no vans with covers - now there are lots.