Usually if a date of birth as well as the baptism date is shown in the parish register it's also transcribed on the IGI.
In 1841 the three children of John and Rhoda were Thomas 6, Charles 4, John 1 mth. In 1851 their children were Thomas 16, Charles 13, John 10, Sarah 7, Lucy 5, Noah 3, Hannah 7 mths. These should give a clue about the 1853 baptisms.
In censuses John was an ag lab.
Rhoda was née Sabey, and appears in my own tree although not direct line. I've done a lot of research on the Sabeys of Mid and North Beds over the years, but not on this Smith family. I've traced your Sabey line back to c1675 in Colmworth.