Again, if Sr followed his pattern and since he did believe in polygamy, it seems most likely they were married in Kenya.
A divorce does not change the fact that there could have never been a legal contract for a US marriage. It was Void Ab Initio.
Remember, the marriage can be attacked collaterally even after parties are dead.
It is not clear as to whether Ann really knew before they were married that he was already married..or only found out later. The story goes that she did find out before the divorce.
I wouldn’t go so far as to presume why Ann filed those divorce papers. There is a person here who works in family law court that believes there never was a marriage. You don’t have to prove a marriage to file for divorce. She thinks Sr never knew Ann was claiming there was a marriage.
The divorce could have been for a marriage in Kenya. Which brings up a law later passed in the UK. The marriage would not be recognized for purposes of immigration if the marriage was before a certain date..1971 or 1972..and one of the people was domiciled in the UK or a country like the UK..such as the US. It is unclear how that would effect a child if he had already established UK citizenship. This would not be relevant if Jr was born in Kenya but would be relevant if born in US.
There is a picture of SR with Ann’s dad..I think in 1959. I suspect she knew he was married..I don’t think it is something he would have kept quiet during the course of conversations over those prior years with people such as her father....but maybe so.