I don’t know about the Sel model, but there is no space in the boot for a spare wheel in the Sports Nav+.
The SN+ has the best sounding audio system I’ve ever had in a car as standard and in the boot it has a sub woofer. When you lift the floor, the space underneath is taken up by a moulded base with the subwoofer in the middle, about the size of a space saver wheel. To have a spare wheel, even a space saver, you would need to lose the subwoofer and get a whole different moulding.