The Earl of Surrey was not only related to Catherine Howard, but he was a first cousin to Anne Boleyn. He was raised with Henry Fitzroy, the King's illegitimate son, who died at seventeen. Surrey was a founder of the English Renaissance poetry movement and with his translation of "Virgil's Aeniad" became the first person to publish blank verse in English.
Michael Winder who plays Charles Brandon's son Henry was also the voice of John the servant to Bishop Fisher who talked to Thomas More threw the door while they were in prison in the Tower.
There was no plague year during Henry VIII's reign. The only plague that occurred in the 1500s in England occurred in the 1590s when Elizabeth was Queen.
About halfway into the episode, Charles Brandon is shown to be still alive in December 1545 but in real life he died on August 22, 1545.
Henry Howard, the Earl of Surrey, never became Duke of Norfolk, he was executed in 1547. Howard's father Thomas died in 1554. The title passed to Howard's son, Thomas who died in 1572 following his role in a plot to assassinate Queen Elizabeth I and replace her with Mary, Queen of Scots.