You really don't need any special pens or markers just for "edge-colouring"!
For darker colours, really any kind of marker in the right colour will do: The colour tends to turn darker when "edge-colouring" (colouring the crossection/edge of the paper) than when you normally colour the surface of the paper, because the ink from the marker will soak into the paper a bit.
That's why for lighter colours, it's often better to use colour pencils instead of markers, because the colour won't suddenly turn darker than you expected with pencils.
Always try out the markers and pencils you have to see if the colour turns out the way you expected (you can simply cut a small, unused piece of paper from the templates themselves, or make a quick test model).
If you really want to use the exact same brand as Haywan, there's a list of stores on the Australian Crayola website that should carry Crayola products: http://www.crayola.com.au/where-to-buy.aspx
But Crayola is a very popular brand, so I doubt that list is complete: I'm sure many more local toy stores and department stores in Australia sell Crayola markers! ;o)
Even if you can't find it in the store yourself, don't hesitate to ask the people who work there: maybe you just overlooked them, or maybe they can order them for you, or maybe they can tell you a different store where you might find them.
And like I said, if you really can't find the exact same ones that Haywan used, don't stress out over it! ;o)
Try out the markers and pencils you probably already have on a small and simple papercraft test model, and maybe you already have all the colours you need.
If not, don't worry too much about a specific brand which might be hard to get, but see which ones you can easily get from your local toy shop or department store for a fair price.
Just have fun, and take care building your models, and then after it's completed you probably won't even notice which kind of markers you used! ;o)
