Hi Annabel and welcome to the forum.
I'm a new camper trailer owner and narrowed my choice down to Johnno's, Customline and Camel. They are all built in Australia and I found them to be of good quality. I went with the Camel Beachcomber, mainly because of the deal I was offered on an ex-show demo model.
I would advise steering clear of the 'assembled in Australia from imported Chinese components' offerings as I've read some horror stories about the quality of some of them. I also had a chance to view some of them at a local Caravan and Camper show and was not impressed. They also mostly use imported 'canvas' which from reports does not hold up too well in harsh Aussie conditions
The best advice I can give you is to start your search with a visit to the Victorian Caravan, Camping & Touring Supershow next month.
http://www.caravanshow.com.au/Good luck with your search.