That is the mark of Britannia Creek Glass, the studio of Rob Knottenbelt in Wesburn, Victoria. He used that name for his production ware from 1984 until a few years ago, and used that mark as a company logo and as a pontil stamp for the latter half of the period that BCG operated. It is a registered trademark, as can be seen
here. His
current website mentions the business, but the logo seems to have been discontinued.
The shape of your bowl is a common one. If you google Britannia Creek Glass and select 'images' you may find a couple of thumbnail photos of similar items, although I think the main photos on the internet auction site have now been deleted.
I don't know about the sticker. Perhaps that comes from a gallery or other retailer.
Trevor