Just for the record - I too had exactly the same issues as very well illustrated in the photos at start of page 1.
It was occasional and was told by a dealer " some do that sometimes". I tried shaving away some material from the tunnel to little success. I applied grease to the underside of the tunnel at the rub point and learned to live with it.
I then had a Panard Rod fitted and it hasn't done it again - not once, despite me trying to get it to do so.
An unexpected benefit of the panard rod.
