I used to polish my windscreen, but when it started raining it smeared and I could hardly see out the screen till it wiped the polish off.

Your window is dirty as said above. Use some good cleaning stuff (Like Mcguires, not fairy liquid ) and you should be ok. Make sure you use screen wash also, not just water You may wanna replace these blades tho...

Cheap ones always caused me problems. On the Skoda I changed blades 4 times in a year and they were still shit, even different makes. but I brought genuine VW Aero Blades (Inc wiper arms from a Mk4 Golf) and I haven't changed blades in over a year

My Esc Cos has genuine Ford ones Wish I could change these to aero blade ones also (genuine ones, not the modified ones to fit any car)