Since I've had car (1 year) the wipers has never run smooth across the windscreen. The ones that were on there when I bought the car were retrofit and were rubbish so replaced with Bosch retro fit but were still awfull, then tried Valeo and still same outcome. They all clear the rain fine but squeak, judder and sometimes bang. Anyone any ideas?? I'm thinking I need to go back to the old style 'conventional' wipers and not 'retrofit'??