The title of the book is "Brockett Family of England, John Brockett and Mary Blackwell" by Raymond W. Madsen which in his work, points out the diffrences of the two different John's of Brockett Hall. His work is dated 29-Dec-1999. He had spent time at the chuch in Wheathampstead, England and Cambridge University to research & point out errors that are in the LDS files and other various palces on the internet.
In his work, he points out that one "John Brockett, Esq. is often noted as "the street". The other John Brockett is usually noted as "Mackrey End".
He has proven that "John Brocket,Esq. of the Street and Mary Gerywaie had five children". All five of these children died young, "including Mary, probably in child birth with Garway, dying in 1619." This includes the son John bp. 20-May-1611, buried 4-Nov-1628. SO, this John baptised in 1611 is NOT the immigrant ancestor." There shouldn't be any descendant from the John bp. in 1611 or from his other siblings since they all died at an early age. The John any of us descend from should be the one bp. 20-Oct-1629 whose mother is Mary Bannister.
I think you have the wrong John. These dates were taken after extensive research in England to once and for all prove the difference between the two John's.