Hi Kylie,
I know it's a long shot but maybe go to an electoral office & search the electoral roll to see if you can find your dad.
If he is still married to Shorron you may find her more easily as that is an unusual spelling.
Last time I went to the electoral office I just walked in & used the computer sitting on the front counter to look names, they even had a pencil & paper there to use.
Good luck
Naomi