Hi Probably someone out there has tried what we have but thought we'd post it anyway.

I know Eriba Folk are an innovative bunch but this could be a very cheap help tip to avoid the troublesome black streaks.

We've fitted long 12" (30cm) long cable ties through the drainage holes in the gutter/awning channel and then a pretty cheap 10 metre length of the awning
trim often used on the white box type caravans.
The cable ties when bent a little divert the run off away from the side and the trim stands out enough to stop runs from the channels.

It's worked brilliantly for us, no black marks hooray.

All the best

Tom

I did the same but the cable ties were to short so just moved the black streaks further down the side of the van. Have put longer ones on since. works really well..

Probably best not to travel with the cable ties in place. They will flap around and scratch the paintwork.

Hi Frantone

Don't travel with the ties in but being plastic they shouldn't scratch really unless there's a lot of dirt under them to cause abrasions.
The rail trim really helps as well.