Transplanting any Xanthorrhoea sp. is a tricky business. They are very finicky plants with regards to transplanting, and there are a few ways to maximise your chances of success.

The potting mix you're moving it to in the wine barrel must firstly be very well drained. You said you've imported some Perth soil, so your drainage might be okay, but if you're mixing in compost too then I'd prossibly add some sand for extra drainage.

Before transplanting, get the hole in the potting mix to a size that you can easily place the entact root ball of the X. Wet the mix very well. Before very very carefully cutting the X. from its bag, wet it thouroughly, this will help the rootball to stay intact. Keep the root ball as undisturbed as is possible during the transplant, and soak it in once you've got it in the wine barrel. You could even cut the bottom out of the bag, place it in the hole and then cut it off the rootball.

You won't know if you've been successful for a few years, as they can take years to die after a shock. But if you're carefull and handle the plant so as not to disturb its root system, you should be okay!

Good luck!

Hi Native Jim.
Well I went ahead and planted it in thw ine barrel. Trouble was, as it was very heavy, I damaged a couple of the yellow roots at the base lifting it into the barrel. I have done as you say and its wet and also put red gum mulch on the top.
Now I pray it will grow and live! :)