hi - your comments about wear have some truth, and we have others on the Board who share your opinion that this feature doesn't necessarily substantiate age, but I'd prefer to see too much rather than too little

You don't mention whether this piece is of lead composition - it should have a good high class ring.
There have been comments here in recent times regarding auction data being less than accurate, and so personally I'd be cautious about taking their word as gospel - they may be correct, but having seen a lot of Irish glass from the late Georgian and Regency period, this one does not show the sort of cutting or colour that would indicate positively c.1800 - 1820.
Unfortunately, there is a lot of glass described as Georgian (1714 - 1830), especially on ebay, much of which is of doubtful authenticity - nonetheless many folk buy these pieces based solely on someone's else's description - perhaps even without knowing for certain what they are buying!!
As I've said, most of the large glass houses have produced copies of C18 - early C19 glass at one time or another - it seems to have started c. 1880 - with quite a renaissance in the 1920 - 30 period, and some of these are very good reproductions, and it takes much experience to spot the difference.
Pieces made in the early C20 were bought and sold as copies - the trouble now is that in the intervening years that knowledge has been overlooked, and some are being sold as period.
Mark West is a respected glass consultant, and his comments to which I was referring occur in his pocket booklet that he did as consultant for Miller's ... 'Glass Antiques Check List' - 1994 ..... a very useful little book.
I don't know what books you have, but for Irish material you will find Phelps Warren's 'Irish Glass' very good - the revised and expanded edition from 1981 (not the 1970 first edition) - and Geoffrey Wills' volume 'English and Irish Glass' has a lot of good solid information.
In terms of general history and information then Charles Hajdamach's two volumes - one on C19 glass and the follow up on C20 material are essential.