Being a breeder and exhibitor of British finches including linnets and gold finches for 37 years and at champion level for over 15 years I'd honestly say that linnets are miles better for song, I used to deliberately breed linnet mules using the German hearts mountain roller canaries to breed with the linnets, I've done this for over 20 years alone.
These were specifically bred for song and have to say that these are without a doubt the best singing European finch and mule,
Don't get me wrong as yes goldies do sing nice but definitely no comparison against a linnet or linnet mule especially if bred from German roller or Waterslager canaries
Sadly though I believe that obtaining linnets out in Aussie is a very rare occurrence but I'm sure that you should be able to obtain greenfinches and gold finches, be lucky with yer search for some quality goldies