The ashtray, to keep the locking wheel nut in.Space under the boot space. The cover of the boot space (it seems to be unfinished hardboard with lumps of foam glued on! It also can't be held up.)
In the back of the armrest you have a spot where you can keep such things.
In the US they have a sliding tray also, maybe if you can get your hands on that for extra storage?
If you buy the Prestige you have a much sturdier boot space cover and decent space beneath it. This is only in the Sport.