Wardie,
I wonder if the fork tube is amplifying some noise on your bike. maybe it's not the cause of the noise. Have you checked to see if the noise might be originating somewhere else like in the hubs or perhaps the cable housing stops on the head/fork tube?
One other thing that I noticed today was that my back wheel was making a squeaking noise. At first I thought it was the brake shoes rubbing against the rim. However, on closer inspection it turns out that the rubber/plastic dust cap on the hub must have gotten some dirt in it and it was partially spinning and rubbing against the main part of the hub and making an annoying squeaky sound. the dust cover on the front hub wasn't doing this, only the rear.
I wiped off the grit and dust on the outside of the cover as best I could and then put a couple of drops of oil in between the dust cover and the rest of the hub and the noise was gone.