Hi......I am assuming this was the Sarah Mott who was, as people believed, cured of bewitchment by the famous cunning man James "Cunning" Murrell of Hadleigh? (The story is in the article "A Wizard of Yesteryear" by Arthur Morrison, printed in the Strand magazine 1900, you can find a copy of it on the files of the Pickingill email list
http://groups.yahoo.com/group/pickingill/ and perhaps elsewhere on the web by now. The stacks of a big library may have the original, I found a copy in Melbourne University library rare books collection)
These wizards, witches and cunning folk are my interest, and I have been struck by how often the surname "Mott" turns up in connection with them. This may be just because there were a lot of Motts in Essex; but I have also been struck by how often these Motts are tailors or drapers or the like....The thing here is there was (according to the folklorist Maple) a family of traditional layers-out of the dead in the Rochford area of Essex, whose name he gives only as "M_". Although not a wizarding family, as JK Rowling would say, they did have a numinous reputation. I am suspecting, no more than that, that this "M_" family were Motts.
You will find the Morrison article of interest in any case, as a window on 19th century rural Essex....