Mine has the half leather in light grey and if you lift the three rear head rests in the back you can easily judge how much cleaning to you to do to get things back to normal.
The leather is strong and hard wearing as is the velour stuff.
I use leather cream and upholstery cleaner a couple of times during the summer months and it cleans up very easily.
As for stains I managed to rid the car of puppy poo ( yes she really did not understand why the world was moving whilst her legs stood still ) child puke ( daddy i feel siiiiii blllluuurrrggghh - 80 mph M1 middlelane ) and the aforementioned chocolate.
A set of full Renault carpet mats cost me £40 and protect the carpet very well. Don't bother with the velour halfrauds ones becuase they dont last five minutes..