There are locking wheel nut removal sockets out there, best bet would be try your local tyre place / garage rather than buying. You could try a pipe wrench seeing it is proud of the wheel rather than recessed but the removal tool would be better.
There is a comment in the 2011 service book, inside front cover, about using a standard nut in place of the locking one on the spare and there should be a single nut in the jacking kit. I know that doesn't help you in any way but may help someone else.
Sorry haven't got the nut size to hand.
Steve