It will probably give you the same colour but not necessarily the same flavour. Biscuit gives toastiness, nuttiness, breadiness. It is available from grain and grape and also I think from some of the other retailers but it isn't the cheapest. If you're not in a huge rush to brew this recipe I can send you a kilo or so through the post (bought a 25 kg sack excitedly during a bulk buy but it never makes up a huge proportion of any grain bill so I have a good wack at my disposal)). Otherwise brew with the brown and try again with the stuff I send you.
All this is entirely contingent on whether it's legal to send grain to south Australia from Vic.