Good list Gridgm
Gospel Of The Horns are indeed very good. The whole Austalian "War metal" (Blackened Thrash) scene is excellent, bands like "Gospel of The Horns", "Hobb's Angel of Death", "Destroyer 666", "Battalian", "Grenade"," Urgrund", "Abominator" and "Atomizer" (they're song "When I Die I Wanna Die Violently" is awesome, pretty much sums up that whole scene)...
Alchemist are from Canberra too
I'll add a few more bands, I think are the pick of the Aus Metal scene:
Earth - Really good DM with keyboards (sound reminds me a lot of Morbid Angel meets later At The Gates, also from Melbourne)
Reverend Kris Hades - Post Black / Ambient (former guitarist from Nazxul and the mighty Sadistik Ekekution, unbelievable Black Ambient stuff, highly reccomended)
Pod People - Doom (Stoner doom, really good riffs)
Portal - Experimental Black\Death ( Weird Atonal, Dissonant stuff, kinda like later Blut Aus Nord put without the industrial overtones, also highly reccomended)
Myrddraal - Epic Black Metal (kinda like Blood Fire Death era Bathory)
Chalice - Gothic / Doom (early My Dying Bride-ish with Female Vocals)
Arkheth - Symphonic BM (I used to live with the guitarist so I'm kinda obligated to plug them, very good, influenced by Abigor, Emperor, old Ulver that sort of thing).