Hello Jackie,
I didnt find a baptism for John - I think I just saw his age at the time of the 1851 census and deducted it - which I know isnt the most accurate way of doing it - its just an approximate guess.
The lady from Portsmouth who wrote to me ( I sent a letter to the Hampshire Family Historian) sent details she found from the Alverstoke Parish Marriage Registers showing John Terlour marrying Mary Ann Mortimore, and stating that his father was also John and a yeoman.
Sally