I looked up "Mary" Jackson in Pretoria many years after his playing career had ended. He was then a practising attorney.
Now, if Billy Millar says that "Mary" Jackson outclassed those two famous halfbacks, Percy Bush and Dicky Owen then that is praise indeed.
Note: I had the opportunity of a long chat with a Mr Tertius Spies of Pretoria who was, as a young man, articled to "Mary" Jackson. He recalled the following: "I once asked Mr Jackson how the name Mary had come to be given to him. He replied that his mother had been of Scottish descent and on the Scottish national day and other high-days she would insist that I wore a kilt."
"This led to much amusement among my schoolmates and other friends. They insisted that if my mother made me wear a 'girl's dress' I should be nicknamed Mary. It has stuck to this day."