I am having all sorts of trouble distinguishing between the 3 different mint varieties of the 1981 20 cent coin.
The Canadian minted coin has 3 and a half claws, but how can you tell the difference between the Canberra and Llantrisant coins?
I have noticed on some 1981 20 cent coins that the text on the obverse is closer to the rim than others. This is easily noticable in the scan below - AUSTRALIA is closer to the rim on the two coins on the right.

Top left is 4 claw
Top right coin is a 3.5 claw (shows up very clearly under my magnifying lens, not so clearly in this scan)
Bottom left coin may have tapering claw (definitely not 3.5 claws)
Bottom right coin is 4 claw (has thicker rim, maybe misstruck)

I have not seen any reference to closeness of text to rim being identifying factor in determining which mint a 1981 20 cent comes from.
Any help would be greatly appreciated.