The mess starts with Elizabeth Mallory, whose third husband (AFTER 1485!) was "A" William Mallery or Mallory - but we don't know which one, and there were several men by that name. It seems highly unlikely that he was Sir William Mallory of Studley. There is no record of any children by this marriage.
Somebody has misfragged THREE William Mallorys onto the Studley line:
Sir William Mallory, of Studley (he belongs there)
Sir William Mallory, of Studley (misfragged into a duplicate)
William Mallory, Esq. (unnecessary duplicate)
In no case could Sir John Mallory, Knight, Sir William's heir and successor, have been a son of Elizabeth Le Bruyn, as he was born in 1473.
Sir John has been made into a quadrigamist, with four wives all living at the same time.
And beyond there it gets increasingly hideously snarled up.
Reworked the third William Mallory William Mallory, Esq. into a plausible Husband #3 - but now we need to figure out where to put him. Hikaru Kitabayashi http://www.genealogy.com/forum/surnames/topics/mallory/2742/ thinks he's connected to the Papworth St. Agnes Mallorys, possibly William "the Draper" or possibly a previously unidentified collateral relative. Considering how *incredibly* well-connected the Papworth bunch were (buddy-buddies with Royalty and high nobility), this makes a lot of sense.
Money quote (with slight editing): "The third [son of Thomas Mallory of Papworth St. Agnes] (in this I agree with S. V. Mallory Smith rather than P.J.C. Field) was William. As Mallory Smith suggests, he might have been the William Mallory, esq. who was the third husband of Elizabeth Bruyn, the mother of Charles Brandon, husband of King Henry VIII's sister Mary and Duke of Suffolk. Another possibility might be that this particular William Mallory was the son of Robert Mallory the Lieutenant of the Constable of the Tower of London and the man I have presumed to be the younger son of Sir William Mallory and Margaret Burley. In any case, assuming this William Mallory to have been a member of the Papworth St. Agnes family would help to more economically explain part of why Sir Richard Mallory of London was later to have the astonishing access to the centers of power which he did toward the end of the reign of Edward VI." http://www.genealogy.com/forum/surnames/topics/mallory/2742/