Each local council on the east coast has it's own sites within 3ks of each town that is free for at least 3 days, if it's quiet you can stay longer and most have toilets with some having showers, all have some means of cooking, either free or a small fee, if camping in the Forrest's you are provided with logs and you pay a fee and get a ticket on entry at a honesty box, if you don't have a ticket you might be woken up at any time by a warden to make a payment.
Get a free site map at any police station or council office or breakdown centre like RAC, it will show all the road side sites and the amenities, the map is produced by the Main Roads Department and is called Rest Areas.
When traveling use the garage rest stops for HGVs, you can get a great shower and food or for a cheap meal find the local RSLs (retired service mans league), good luck. John H.