Thanks for replying to my request!!
I'm sorry but I have so very little info to go on that I don't believe that I would be of much help to you. I don't know where John Sinclair was born but I have been told that he was a Scotsman with a strong Scottish accent. I would presume that he grew up in Scotland before travelling to South Africa during the 1960's.
I hope this is of some help to you. Please contact me if you think you have anything for me to go on or whether I could be of any further help to you.
From: Shirley Bowers