We've considered an Eriba towing cover and have seen photos of some hand made ones. Probably quite easy to make as a two or three piece (one top and one or two bottom bits) each piece sliding into the awning and skirt rails before being buckled together in the middle.
We have two reservations.
a) No matter how tight the cover fits, will it abrase the paintwork and acrylic?
b) It will spoil the whole character of the front of the Eriba when towing. Therefore patches to mimic the front windows is a must
When we bought the Touran with its short tail end, we had mud flaps fitted which seem to do a pretty good job of stopping any stone chips coming from our wheels, at least. Won't help any flying debris from elsewhere, of course.
Randa