it's cheaper if I go to Camden as the approaches are based there and I would be able to save some cash.
To paraphrase an old advert for Dassault Falcons, "Cheaper isn't better. Better is better." Yes, instrument ratings are expensive, but the corollary of that is that saving a small amount on something that costs a large amount isn't necessarily good value. You have to ask yourself, when you are in the sh*t, with an engine out, cloud down to the minima and several thousand feet of mountains around you, do you want your training to have been carried out by the lowest bidder?
That's not to say that the best schools will be the most expensive, but I would honestly suggest that your key criteria for choosing where to do the rating should be the quality of training you receive, not the sticker price.
In addition to the suggestion of Bill Whitworth, who I have only heard good things about, you may want to consider some places further afield. Peter Bini Flight Training in Melbourne seems to keep coming up as a recommendation here (can't vouch for them myself, so someone else will have to fill in details). In the opposite direction from Sydney, Bob Harris up in Innisfail has a very good reputation, on-site accommodation which I can't imagine being more expensive than Sydney, and a plethora of contacts in north Queensland (which may not be terribly useful right at this point in time, but when things pick up again I'd wager you'd be more likely to find an IFR job for a low-time pilot in north Queensland than Sydney...). A number of people I know swear by him (no doubt having once been sworn at by him
Wherever it is you chose, I'd suggest you take the time to find out what is and isn't involved, what the prices cover, what the instructor or instructors are like, etc. A little bit of legwork prior to starting might save you a lot of grief in the long run. Personally I'd steer clear of the mass production style of operations, though I am sure there will be others who will disagree with that sentiment.
Good luck with the rating!