I am appalled to see that this crap is still going on. I would volunteer to contact Corporate Affairs Victoria to see what can be done, but Little Bird is in NSW - perhaps someone there could contact the NSW counterpart authority?
There is another technicality which we have all missed, including me. Under the GST legislation, there is no compulsion for a GST-registered supplier to provide a Tax Invoice for any purchase under A$50, so technically it could be argued that if you only by a basic Arduino board you couldn't demand a Tax Invoice.
My larger concern is that Marcus is trading using an ABN, which obligates him to do the paperwork properly, and yet there appears to be none for most customers on this forum.
I will put my hand up to investigate this with the ATO and let you know what I find out. Hopefully one of you will be able to get some info from the NSW statutory bodies.
If we're really lucky, Marcus may even be reading this and have an epiphany .............. 