I had this problem on our Tintop (Citroen). The dealer said the same as above - 'nothing could be done'. But when polishing the chrome on my Roadster with Solvol Autosol I thought 'Would this work?' A quick wipe brought an instant improvement, and less than fifteen minutes work eliminated them all. I then dealt with my Son and Daughter in law's cars (much worse marks than mine - they cover their two boys in sun lotion) and they (the cars, not the boys) now look pristine!

R4