hey Barry. I found some great plant ideas at my city's botanial gardens. I noticed you live in Australia. The Huntington Botanical Gardens might be a good place to start. they also have a website which you might be able to get ideas from:
I would choose plants that do well in boxes and that provide screening but also color, as you want something pretty to look at on your patio. we don't use the metric system here, so I don't know how much space three metres covers...sorry.
I hope this helps! :)