Good point, sorry wasn't thinking properly - although the worst case would be to leave the unit behind the headunit (there is room to the side) and run a USB cable to the glovebox, although this would block access to the SD slot
That's what I was thinking. I'd like the unit in the glovebox so I could get access to the SD slot if needed. It's no big deal if it doesn't stretch, though, as long as it fits snugly beside the HU, that will be fine.
It should be here tomorrow so I guess it will just be trial and error until I find the best location for it.