Peter, the inside of the car behind the circular cover is unreasonably clean and tidy! Mine looked, the first time I looked, a bit different...
I have found that road muck comes in through the louvres and makes the area of the tank look "grubby".
I see from your photos that MMC continue to mount the rear speakers using a bit of wood, with no effective enclosure. I do wish they would learn even a little about audio engineering. I fitted small boxes behind the speakers, resulting in a significant sound quality improvement.
The very first Plus 8 models had a side cover storage slot as you describe. But it was a very tight fit and quickly discontinued.
