I'm posting this in case its of interest to anyone who might want to use this otherwise hidden space in the back of the car.
If you remove the expanded foam from under the boot floor where the charge cables are usually stored along with tyre repair kit, there is a large plastic storage well just in front of the rear bumper. The expanded foam is held in place by 4 metal star washers over plastic studs just behind the back seats. If you persevere you can unscrew and remove the washers. Its almost like there was an intension to create an accessible storage well in the back but for some reason it wasn't followed through. If this was to be used e.g. for items that you don't need very often, the star washers could be replaced with something that is easier to remove.
If you remove the expanded foam from under the boot floor where the charge cables are usually stored along with tyre repair kit, there is a large plastic storage well just in front of the rear bumper. The expanded foam is held in place by 4 metal star washers over plastic studs just behind the back seats. If you persevere you can unscrew and remove the washers. Its almost like there was an intension to create an accessible storage well in the back but for some reason it wasn't followed through. If this was to be used e.g. for items that you don't need very often, the star washers could be replaced with something that is easier to remove.