I think this is a studio piece. Noting you are in Australia, I know of two local glass artists with initials BV. I discount Bettina Visentin as the maker for several reasons, but Barbara Veall is likely.
Barbara Veall graduated with a masters degree in 2006 from Monash University, majoring in blown glass. She was a finalist in the Ranamok Glass prize in 2002 and 2003. She has a page on LinkedIn, which indicates she now runs her own interior decoration business in Melbourne.
My evidence for BV being Barbara Veall is all circumstantial but otherwise strong. Apart from the short list of possible local candidates from which to draw the initials, her prize entries in both years of the Ranamok were blown frosted glass vessels with polished finishing touches - just like your decanter. Colour is used sparingly in both cases; in fact in one year the objects were clear glass with the only colouration being the whiteness of the frosted finish. She seems not averse to being identified by her initials: the business is called "BGV Interiors".
You might try asking her (making contact through LinkedIn or the business). Please report back with any information you obtain.
Trevor