
matty-j.
Gotta agree 100% with Maple. The roots wrapping around the trunk is going to be very difficult to unravel. You will snap a few of the heavy roots off when you straighten them up. And because your going to lose a lot of the root system, your going to need to cut back the branches pretty hard. Not sure about Sydneys winter temps. So I can't say for sure if you want to do this now or wait till spring.
I wouldn't worry too much. Callis are really hardy. And don't seem to mind being in water for awhile. So when you unravel it all, I would suggest leaving the whole root ball in some water for a couple of days and see how she goes. Maybe add a cap or 2 of seasol. Or do what KC suggests. Get your moneys worth.
In future,

, I suggest, only buy from reputable bonsai growers, or local nurseries/places. I will always pull the plant out of the pot at the place. I've done it in front of staff, they don't mind. Brush the top soil to the side And see whats there. In general, not root bound.
Anyway, I hope you take this advice with a pinch of salt. I did the same thing (root wrap) when I first started, and it survived, but I did so much damage to the nebari it was never going to be a good bonsai. And its just a calli in a pot now.
Matty, I truly hope it ends up being a great looking bonsai for you.

,
Woody