I would recommend Giles Tremlett's biography of Catherine of Aragon because he used the Spanish archives. For example, he gives details of the Zaragoza tribunal into Henry VIII’s request for an annulment, as well as the Blackfriars court. See http://reviews.theanneboleynfiles.com/catherine-of-aragon-henrys-spanish-queen-by-giles-tremlett/532
Catherine Fletcher's book, "The Divorce of Henry VIII", looks at what was happening in Rome, with the ambassadors, during the negotiations for the annulment, so you may find that interesting too. It doesn't give a Spanish perspective, but it gives details of what the ambassadors were all doing. See http://reviews.theanneboleynfiles.com/the-divorce-of-henry-viii-by-catherine-fletcher/890

CLICK HERE FOR MORE QUESTIONS