LOL, I got so lucky with mine haha.
IMO, just do your best, make it look respectable (legal/clean as you can), go down with a good attitude (dress properly.. no thongs, singlets/cap backwards etc) talk to the guy, just bought it fixing it up for rego, stupid previous owner did that, so I fixed it it this etc etc.
If you still fail, you get a list of what NEEDS to be changed to pass, then you got 30? days to fix that list and you're sweet.