As a matter of interest are there two sliding cup holders in the front, or just one fixed one?
Neither - there are two cup holders, one inside the other. You can pull the top one out and push it back in behind the first.
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?
I didn't know about the tray, but anything in the back of that is actually visible through the front window. Apart from looking untidy, there's a security issue. I think if the second cup-holder was in place, it would hide more, but the tray would probably be better.
If you buy the Prestige you have a much sturdier boot space cover and decent space beneath it. This is only in the Sport.
Yes, the under-boot area on the sport/sport+ has a polystyrene filler with holes cut in it for the tyre pump etc. (and some spare, presumably for other markets which need things like warning triangles). I had assumed that this could be removed for more space, but I think it's pretty structural. The hard board wouldn't take much weight without it - I have fit a small blanket, a couple of high-vis and a thin rain coat in it the holes, but that's it.