Well here is my idea and it works.

Now all you need is this

and from the back

Yes the door opens and the cover stays in place

Mine needs to be bigger and grey to match the awning. But the prototype works.
All I used was the suckers for the fairy lights on windows or those silly signs that swing in the back windscreen (mums Taxi)

Hope this works for you...
Working on the skirt now as the fig of 8 is a tad too small.