Hi Ros
Catherine Imrie Mackie was b. 21/12/1895 in Kingsbarns, Fife Scotland
Her father was John Mackie her mother was Catherine Peebles now Catherine Peebles's mother was called Catherine Imrie hence the middle name
Andrew Mackie was b. 05/07/1892 in Kingsbarns, Fife, Scotland same mother and father as Catherine
On Andrew's enlistment record it states he was b. 05/07/1893 one year out which is neither here nor there
I've tried searching the Australian records and as you say it's quite pricey not like Scotlands People where you buy credits, also you have to apply in writing for to access the record in Australia by mail.
George