Funny enough, I picked up my car last week and have suffered the same annoying rattle from the front dash (front doors are ok). Sounds like its coming from beneath the front instrument panel and is only audible when you're covering rough patches of asphalt. Real annoying though. I would have expected better from a VW, especially having come from a faultless Ford Focus.
Have relayed my concerns with the dealer, who are happy for me to bring it in, but I would rather persevere with it a bit longer, before they start dismantling things and make things worse! It may be a case of letting it bed down. Still not a good start though.