Hi Rhys
Yes - John Milner Jenkins was the son. I have the family on 1851 & later Census but had nothing for 1841. Are there any Cowles at all listed on that Census? The son, John ( my gt. gt,gt grandfather) appears twice on 1871 Census one entry presumably in house of his then employer. Florence Jenkins & William had another child William Hercules Jenkins Cowles ( found in family search org christening records) who never seems to turn up anywhere later. However on later Census ( where John is residing with Jenkins relatives William Hercules Jenkins is listed as a son.
I have ordered the marriage cert for Florence & William yesterday to obtain details as to further clues re Wm's father and Florence's parentage which might help.
Thanks for checking, Rhys.
Belle