Ahhhh you know what i'm wondering guys.
My brother isn't that old, only 28 (I think) but i'm wondering if he is having a bit of a senior moment and actually bought a 2.0Gb USB stick? and it's showing up as 1.8 Gb or 1800Mb free?
Thinking about it £10 for a 20Gb (or 16Gb) USB Stick in a SHOP would be very cheap.
Shops In the UK tend to live in the dark ages and I still genuinely see 4Gb sticks for £15.
I might pop round there tonight to see, or he will find out when he tries to backup 16Gb worth of stuff.