Hi I was wondering how u went with this search? I think we may be looking for the same people?
My dad was called Gregory John Markos..... And yes the last name was change when they came to Australia.
My dad was born on 1959 so I think it may be his grandson...... Or so to the person your looking? But my grandfather had 1 sister and 5-6 brothers.....
Hope to hear from u.