Hi Griff,
We stored our first campervan and 4WD in a lockup on the left hand side of town as you head in. Cant remember the name but there was a large caravan park on the oposite side, we stayed there there for a couple of nights ( big servo there as well) then put our rig in a lockup whilst we went to Bali for a couple of weeks. We had our own padlocks and they give you a swipe card to enter the set up. Very secure and not that expensive when you compare losing your rig, also cyclone proof storage as well, very handy when we went. We picked up our van around 2:30 am and having the swipe card to access when you needed was great.
Hope this helps, if you want you can PM me and I will make a bit more effort to find name for you.