If at all possible, I would highly recommend you get your hands on the book "Heirloom Machine Quilting" by Harriett Hargrave and or "Guide to Machine Quilting" by Diane Gaudynski. Not sure how easy they will be to find in Australia.
Both explain everything so well and have loads of pictures and Harriet's book has some continuous line designs in the back of the book you can utilize for ideas and inspiration. Like CKcowl, I quilt on a longarm so the quilt is pretty well stabilized because it is loaded on the rack. Ditching isn't necessary but I will do it on 90% of custom quilts. I do it because it really gives definition to the piecing and, to me, just looks nicer. If you ever plan on showing a quilt in a quilt show, judges want to see things ditched. But on a domestic, ditching is a chore and can quickly suck the joy out of quilting for you.
Quilting on a domestic requires the quilt be stabilized so you don't get shifting, tucks or pleats worked into the quilting. Many DM quilters use glue or spray basting to help stabilize. Others use safety pins, LOTS of safety pins. Harriet discusses this in her book as well. So does Diane Gaudynski in her book "Guide to Machine Quilting" another excellent resource. Both are advocates of ditching prior to machine quilting. That said, they do specifically say it isn't necessary to ditch ever single pieced seam of a block.
I think that if you baste well and the quilt is a utility quilt as opposed to a show quilt you don't have to ditch. Especially if you plan on doing an all over design.