I, too, had a squeaking/rattling noise coming from (I thought) the NSF suspension on my GTI, especially at slow speeds. Fortunately, I was able to download the evidence from my dashcam because when I first took the car back to my dealers they said they couldn't hear it and then, after showing the Service Manager the video on my PC and, after we had taken the car 400 yds down the road on a test drive, the technician heard it too. But he said he thought it was coming from the rear suspension.
Anyway, he heard it so the car was booked in for a warranty repair two weeks later and, this time, another technician test drove the car, then phoned me to say he was convinced the noise was actually coming from the NSF suspension, which was what I had said initially. Three hours later, he phoned me again to say that he had adjusted the suspension mounts on both OSF and NSF, and applied a generous application of "Lithium grease" and was convinced that the problem was gone. I think he's right because a week on and 300 miles later and I haven't heard a single squeak.
However, I'm very lucky to have such a good and honest service manager because he doesn't seem to be 100% convinced that his chaps have resolved the problem for good. He is clearly aware this is a known issue and asked me to let him know, immediately, if the problem returns. If that happens, he intends to replace the suspension mounts etc, under warranty.
So, I shall be keeping a very, close eye (and ear) on the problem. But, so far, so good.