Not so far, Nigel, but we bought it because we thought it was going to tip it down the weekend we were at Horwood for Silverstone. so it hasn't been on the car for any length of time!
It's a shame if it is causing the damage, as the overall design and quality is so good and it's surprising too, as the grip of the magnetic edge is not hard. Are they scratches or are they marks? Perhaps the sun has softened, melting the edging that the magnet is coated in, causing a deposit to form on your Mora's paintwork, which if so, would then harden when the sun goes in and the bodywork cools, making it hard to remove without rubbing away the surrounding paint. :-ss
Sorry not to be of more help, but nice to hear from another Mora Zedder, :ymhug: how about some pics!! Will look out for some now!