Ok, in the interest of info sharing for anyone else experiencing the same, an update on my wiper issue.
From day 1 the wipers juddered a smeared badly. An impromptu visit to the dealer cured the juddering but the smearing remained even though they replaced the wipers. Car was booked in last friday and they replaced the arm on the drivers side, added a 3rd set of wipers and now it is 99% perfect.
The main thing is they have reported this back to the factory and i havnt had to put my hand in my pocket!