I realised after I had transcribed the whole of my Great Grandfather's will, including the page I missed the first time around and divided it up into paragraphs, that the codicil was missing - that all important codicil which just may mention the twins.
I spent all of yesterday transcribing the will and saving it as an html document but without the codicil it is worthless as the wills of the other siblings mention parts of the "Hundreds of Onkaparinga" which they were not allotted in the original division.
There was a note at the bottom of the last page saying that the codicil was separate from the rest of the will and gave the page number where, hopefully, it will be found.
I have sent in a request, an explanation and directions where to find it and hopefully I will eventually get it and we can sort out just how many and who got what as far as the land goes. Great Aunt A. seems to have ended up with quite a lot of it and in the actual will she didn't get a share in the agricultural land at all, only the house and its surrounding land.
In the meantime I will finally get back to the much-married Davies branch of the family which should keep me busy for some time to come