There are services and books avail (eg: "estimators" and "estimation books such as Rawlinsons guide") that are current, and provide the set / standard rates for all trades ervices and materials.
I too have had a gut full of rip-off merchants, but not just tradies. So, the best way to get even is to eduacate yourself (with such info as provided from above mentioned) and that way you can negotiate, or refuse prior to accepting the service/goods.
Bearing in mind, plumbers and sparkies are the only servces required to be "licenced", so they kind of have the market cornered, unfortunately.
So, if you can't beat 'em…join 'em. I am! I am so over rip-off builders, I am now doing a carpentry course!

A suggestion may be to call up the companies that actually do this (I have seen them advertised) and pick their brains. Maybe pretend you are a home owner to see how they would go about trying to convince you to sell yours, then apply the same strategies! Good luck. There's obviously money to be made.

After thought: Are we not able to send private messages to each other now like we used to be able to? Cos I'd really like to contact you Hutch to ask you more on this subject!

Hey, make sure you DEMAND the interest  that your solicitor would have acrued from the deposit he was holding in HIS trust account. Might not be much, but it sounds like doesnt deserve a damned cent from you. Can you tell us who it is so we can all avoid him like the plague? ( are names allowed to be named on the forum???)

wow! What a nightmare you poor thing! My heart goes out to your poor folks. I have been forced to have to pay a compulsary road levy before, but only about $3k, that was bad enough.The worst thing was, that originally there were already sealed roads, then the dev't co tore them up & refused to re-build them. So, the saga went on for many years, about who was going to pay. Council apparently figured they needed to force the residents to, or face up to paying themselves. (as if a council would!)
I felt so sorry for the elderly,poor folk that lived there. Some had to leave cos they couldnt afford to pay. Heartbreaking.
Then,just to top it off, when they did start, it took MONTHS for them to dig out the roads, so we had to drive in boggy mush. And when they dug up my street (my house was on high side) they dropped the level too low, so I couldnt get the car in or out of my driveway anymore! (it bottomed out). Then shit really hit the fan. I started leaving my car in the middle of the road with a sign on it "this is councils idea of justice…..I paid $3k for this!…" etc. Then I started legal proceedures…. Then I got the local newspaper & residents (of which by now there was a community support/lobby group) & lastly the local councillor involved…. It got ugly.
They had to re-do my whole driveway….still didnt work….months go by with no access to my driveway…..many,many phone calls & arguments & visitors…..I got so fed up I sold the bloody thing to someone who had a 4wd & strangly enough didnt care! (and I made a great profit on the property!) Moral of the story……fight as much as you feel you can, but get out if it's too much, it aint worth it, heart breaking as it may be.Sometimes we need to be "forced" on in life. Sorry if this is no help to your situation, but maybe it will shed some light on it. Good luck. Can you report back? I am particu;ary interested in what will happen.