Your message re the third wife, read:-
She was the niece of Fr Clayton, Parish Priest of Cleator but I can't get a fix on her.
I have given you the fix on her by going through and looking at each member of the Clayton family.
You now have her parents names, her maiden name, her birth place. You would need to purchase her birth certificate for the exact date, I do not do that. There was no UK marriage for the couple.
I believe that BMD records housed in Cape Town from 1895 - 1971 including Western Cape, Northern Cape and Eastern Cape are now open to the public. You would need to pay a researcher to go to the archives and explore the marriage. Sorry I cannot help
Good Luck
Sandra