I made some dead man's hands from teak, They are cut to the curvature or the outer tyre circumference and are cross halved to slot onto the lower timber cross member where the spare wheel holder fits on! and screwed on to hold in place. when the centre fixing is removed the wheel remains in place with the tyre sitting on these aid's thus protecting the rear alloy panel. If I remember correctly the diameter of the wheel is 600mm so a diameter of 300 for scribing the size, or just draw around the tyre laying on a piece of card, cut it out and use as a template.
