Hi Gillian,
Thank you for the information. As you say I will have to get in touch with Western Cape Archives for a copy of Watson's Estate file.
I'm very thankful for the information you have given me but I'm now trying to find out more about his offspring Benson and Arthur. In a passenger list of 1924 they are both listed with a initial "C".
I have satisfied myself with his daughter Florence Mary who married, and his son Watson William who passed away in 1918.
Regards
Jim