I think Ross is right! The identification with Tony Hanning fits with our (rather imperfect) recollection of what we saw in a gallery, and the dragonfly is an image he has used. The precise carving by sandblasting is his trademark, too. I now think the faint signature on the original piece of this thread is indeed Hanning's. (In that case, the coincidence between my guess of the sig and the maker of the blank for Ross's bowl is just that - coincidence.)
Here's another example of Tony Hanning's sig (from 1988 and on a blank blown by Richard Morrell). Apart from Hanning's tendency to give his "exhibition" works strange monosyllabic names, there are some other mysterious letters D.J.S.C. 7.11. I believe this inscription relates to the gallery where it was exhibited, on the seventh floor of the David Jones department store on Elizabeth Street in Sydney, which operated as a fine art gallery from the late 1920s until the early 1990s. Towards the end of the period the emphasis of the gallery became more high-end Australian crafts rather than international fine art. The gallery hosted several exhibitions in association with the Crafts Council of Australia in the 1980s.
That's a long-winded way of saying that the letters on your bottle may indicate the retail outlet to which it was consigned.
As I said in an earlier post, I can't recall where we saw a bottle like yours, but almost certainly it was within the last five years and in a gallery-type retail outlet. I have no recollection of the price, but it was clearly high enough to prevent me buying it. Your bottle is likely to be quite valuable - multiple 100s of dollars, rather than 1,000s, though.
Trevor