here is the tyre carrier i've made. Like Steve F i used a slam shut latch and sub axle (thanx for the idea steve)
I also made a replacement bumper which doubles as a towbar.
There are really 2 stages to this carrier. ONe for around town where the tyre sits nice and close to the tailgate, and 2 where you can bolt on 2 jerry can holders for camping.
Here is a rear shot with the jerry cans on
and from another angle
open
no tyre now
and now with no jerry can holders on
There you go