Can someone help, I have the world's most annoying wipers. On the up stroke they make that squeaky grinding sound (like when you rub your finger on a wet mirror). I have genuine aero wipers on that are a year old, I use screen wash in the correct quantities, keep the windscreen clean (slightly OCD about that), the windscreen is 3months old and I have thoroughly taken apart and re-greased my wiper mechanism in June. It's doing my head in and I'm out of ideas? Should I bend the arms one way or the other by a few mm? Or is it new blades time? Any ideas chaps?