If the signature is on the bust they are Obverse 2 if the signature is between the bust and the border teeth its Obverse 4 . They both appear to be Obverse 2's. Obverse 3 is same as Obverse 2 but the colons after D are in line with the border teeth and the R of REG points between two teeth
Die fill to the ‘0’, commonly seen. I still suspect that the dot is corrosion given its lobular shape and adjacent surface granularity. But a definitive answer could only take place under a microscope or by finding identical duplicate coins.
Jerry
Congratulation Paddy, it's a very very good find, I wish I can find the same in auction or elsewhere at a fair price too. By comparing your pictures with those in link provided and also discussion in another forum and taking into account toning and minor rim nick, I think it's likely a geniue one.