Well at last I have just found out what the inflatable thing is, so i will put an end to your wondering too.
Aparently its for ski's!!!!!
Yes ski's, coming from the land of the Alps the kind people at Renault have taken into consideration the few who enjoy this sport.
So for the remaining 99.9% of us, we can put it to good use as a secret stash place when you cant be ased to use the boot.
As for the switch in the middle i too have no idea and would appreciate any info and lets hope its more useful than the ski compartment!!!
x x