In the 1911 census she is single and no record of children.
What evidence is there she had children
I see no likely marriages after 1911
and the only Hudson child born to a Hudson I see in Warwick was in 1925
Hilda F Hudson
Which is possible but very unlikely as Sarah ann would be 55 years old.
Just because there are two grandchildren in the 1911 census that does not mean they are hers they could be from any of Charlottes children.
Have you looked here for more children
Hope this helps