I never really had judder, it was just the old wipers worked OK on the out-sweep but seemed to lift slightly on the return, leaving a smear exactly in the centre of my vision. The dealer had literally no interest, saying I needed to clean the screen better.
It was really irritating so I did a lot of messing around myself to get a fix.
Cleaning the screen with a quality screen cleaner (no effect), cleaning the blade with a general car wash solution and wipes (no impact), increasing the washer fluid additive concentration (limited improvement), wiping the blade with a thin oil (recommended by an old car mech I know, did help but didn't last a week), slightly tightening the arm to increase pressure (slight improvement).
Changing the blade has fixed the issue immediately - I guess next time I have a question I'll check on here first!!!