Good luck.
Yeah they don't do the legal checks, and in fact if you ask the selling agent about something dodgy they often do the equivalent of putting their fingers in their ears and going "lalalala" if they know something they have to disclose it so they go out of their way to not know anything.
We're on our third house now and it was bought just under a year ago from the owner directly rather than an agent. It was by far the best buying experience.
My advice would be to give your details to all the agencies and let them know what you're looking for. Often they will have open homes before they go onto the market and send out a weekly emailed newsletter (a good idea would be to use a burner email account so that when you do buy a house you no longer get spammed). Also set up alerts on trademe and don't bother waiting for an open home, get in touch with the seller straight away.