I have a knocking noise in the front also and it's getting worse. Trouble is there are a multitude of possible causes. I've read heaps of threads on knocking noises in the front of MPS6's and they're all caused by different things.
In my experience the weakest links in a suspension system are the sway bar end links and D bushes because they're exposed to very high stresses and usually fail first. That's where I would begin my investigation.