Taffy4740 on Family Tree Circles

I believe that my great grandfather, James Leslie King (1862-1924), is the son of James Alexander King-Macnamara and Georgina Clarke, who migrated to Australia from Scotland with their four eldest children some time between 1857 and 1864. The family name is variously given as King-Macnamara, King Macnamara, or Macnamara King. If 'my' James Leslie is from this family (and I have good reason to believe he is), why he dropped the Macnamara is a mystery I would dearly love to solve.