It's a pleasure Rob, ....don't quote me on this

.... but I don't think English crowns of the period had this distinctive style and shape (the one in Australia)....I could be wrong & it may be a red herring ....but if the stopper is French (& yours looks like a French ducal) then it could be that the glass is also French...but I can't comment on the glass !
Best of luck with your investigations ! Ta, Mike.