Looks like no one read my original post.
All the vinegar on the planet will not fix this problem, so it's utterly pointless suggesting it! Unless someone has got some magic formula other than the dozens I tried, then a new screen is the only fix that actually works!! I tried everything suggested on here, pointless.
There is nothing wrong with the wipers or the blades. The screen - or whatever sh!te is on it from Wolfsburg is the issue. Sounds very drastic I know, but it's all that worked for me. The dealers fobbed me off with "washing solution" but until I got them to replace the screen for a different problem entirely, the squeaking just wouldn't go away.
Now the same wiper blades that drove me fcuking crazy squeaking are today perfectly silent, on a different new screen. I never have to wash the blades or wipe vinegar on the screen, they just work !