I recall our first (early 2012) chassis had some form of shield added in late 2012 when we had the (very noisy) first bevel box replaced after a couple of thousand miles. This was to address the huge amount of road water/dirt that was getting into the "cabin" via an opening around the bevel box and seat belt reels. Cannot remember any more on it and not so relevant as we added a mudguard and the chassis has been repaced. In other words, the early cars had a particular problem with dirt/water in that area which was seemingly fixed....
Yes, the area behind the white closed-cell foam in my photos is covered by a reasonably well-fitting plastic moulding (held in place with 4 tie-wraps). As you say, I believe this was retrofitted to the early cars. I added the foam to hopefully catch at least some of the fine dust that manages to make its way past this plastic moulding!
