Does the noise come from the blades themselves or the motor? If it is the blades there might be a film of wax or some other valeting solution on the windscreen. You could try to clean the windscreen with a little methylated spirit on a cloth. Or vinegar and newspaper, the traditional way to clean glass.
Sorry to hear your havin a problem with the wipers, mine are quiet, and I forget there on sometimes when they come on on there own on auto, I would pop back to the dealer and. Tell em, possible a mechanic has lent on them and bent an arm maybe cos they shouldn't be scraping after one day, best get it checked.
I tried the vinegar trick and it has helped, but not fixed it completely so I will try again tomorrow. Got a courtesy call from my dealer yesterday and he said to bring the car back and they will try to sort the problem if I can't do it myself.