Had the lower universal joint (column behind pedals) replaced a few months ago to try and cure a knock. Did not make a difference. I showed a technician at the dealers yesterday and he had a quick look and said it is looking like the steering rack. Going in on Monday for a few days but I expect it will be longer if they have to order the part. Basically there is a knock when rocking the wheel left to right, doesn't even have to be much movement. There's a knock when going down off speedbumps/driveways etc as well.