Oh, OK Philip. I wasn't sure if you were in UK looking for info about what happened to him after he left, or here in Aus wondering about his background.
George Manson Macaskill b1905 to Johanna Macaskill, father unknown, in Halkirk, Caithness. As you know, but for others reading this ... he emigrated to Australia on the SS Barrabool which sailed from London in December 1924. He married Rita Jarred in 1931 and lived most of his life in the area around Nhill in Victoria. They had five children, all still living and many grand, great grand, and great great grand children. He moved to Mildura late in his life and died in 1952.
His mother was Johanna (Johan) Macaskill b1871 to John Macaskill and Margaret Mackay in Edinburgh, Scotland. In addition to George she also had Margaret (Maggie) Ann Macaskill HARPER; Johanna Macaskill GIBSON; and Catherine Innes Macaskill. All were by different fathers and she never married! Johanna died in 1946 in Halkirk.
There are four or five Mansons as possible fathers for George living in or around the village at the time. The pattern we see from Catherine was to use the father's surname as the middle name (James Innes was a neighbour and almost certainly Catherine's father).
John Macaskill b1840 to John Macaskill and Catherine McLeod at Shulishader, Isle of Lewis. He was described on official documents as either a Gardener or Journeyman andmoved to Caithness between 1851 and 1859. He married Margaret Mackay in 1859 in Bower, Caithness, and died in 1877 in Dunnet, Caithness.
Margaret Mackay b1833 to Alexander Mackay, Cottager, and Ann Weir (Whier) in Bower. She died in 1900 in Halkirk, Caithness.
John Macaskill, Crofter, b c1798 to Angus Macaskill and Ann Mackay at Shulishader, Isle of Lewis. He married Catherine McLeod in approx 1820 and died in 1882 in Stornoway, Isle of Lewis.
Catherine McLeod b c1795 to George McLeod and (Ann Mackay - according to Catherine McLeod's death certificate, I can't verify this and suspect that this is a mis-remembering by the family).
I have various documentation copies and some additional info. I am planning to write up a short history of the Macaskill line so shoot me your personal email (contact details by clicking on my name above) and I'll keep you up to date. I also have some info on the Jarreds.