Hi and welcome!
I don't recognise the piece specifically, but the mark looks a bit like the mark for Mtarfa, but upside-down.
The appearance of the work is not inconsistent with their output, but you say it was bought in Australia.
Mtarfa is from Malta, I don't know what the liklihood of Mtarfa turning up in Australia is, although glass does travel a lot.
There are a multitude of Australian artists whose names and work I do not yet have the pleasure of being familiar with. It could be something more local.