Sorry to chime in but as new owner should I be buying the official VW screen wash? I used any old stuff in my MK 6. Reason for asking is I have read reports of cheap screen wash clogging the system.
Depends on whether or not you have fan jets or the pistol type.
It doesn't need to be the official VW stuff, but it is recommended to use screen wash that's compatible with fan jets. I bought a small bottle of highly concentrated Wurth screen wash off eBay and that did me fine for a few years. Cost me about £5 IIRC.
Some will tell you it doesn't matter if you use fan screen wash or not, but I decided to err on the side of caution.