Mary Sheriff was the 78 yo witness.
I, too, have been following this thread since reading OP with coffee about 46 hours ago.
So here is my "2 bobs worth"
Regarding the Christian name "Mary Ann"
1. James Hall (in newspaper report) refers to the child as "it" - never a name.
2. It occurs to me that, upon Hall's arrest, the child would have been taken into care and it COULD have been that the caregivers (having no knowledge of a name) gave the child the christian name then and there. After all they have to be able to call the child something....
3. By the time this gets to court, Mary Sheriff the witness refers to the child as "little Mary Ann" as that is how the court is referring to the child .... But this is a recent name bestowed on the child by recent caregivers since the arrest of Hall ......
I don't want to be a wet blanket as you have all done such wonderful work

I am also intrigued about the "given" surname of "Williams".
And another query, possibly legal, but would there be leniency given to a perpetrator if the abuse was to their own child as opposed to abuse to a child "purchased" (as one person in the court alleges). Hall is a nasty piece of work and I can't see that he is likely to be truthful - just interested in saving his own skin.
The punishment given to Hall is laughable.
Amazingly sad and horrific case of child abuse.
This Mary Sheriff is someone, I think, that is worth looking into as well
Cocksie