About 6 bolts hold the tub to the chassis. A couple of small bolts on the fuel filler, unplug the lights etc, then a lot of hands and lift. The hardest part is getting the fuel filler gromet to seperate away from the tub. You may need somebody to do that whilst everybody else lifts.
If you have access to a fork lift, run it through the wheel arch area under the tub and use have a couple of people to guide the tub away from the cab as you lift it (or you will take paint off the rear of the cab etc.)
(I used the fork lift method)
As you lift up slowly you have to also move the tub backwards to clear the cab
When you have removed it, remeber to sit the tub down on something soft upside down. (or you will damage the tub)
I don't think I have missed anything.