When working on lining the back doors, in the snow, the other day, I threw a plastic groundsheet over the doors and thought at the time I need to get something made up. My initial thoughts were a 'material cover' attaching to a set of roof bars and then down to the edges of the door with a lip running down, all clipping in somehow - the thought on the roof bar/raised edge was to provide water run off.
I don't have a sail maker in West London so I better get my sewing machine out at some point...... or drive to the coast
Just a few other jobs to complete first.