I have not looked at the films you quote, but from the titles I can suggest the following:

0454951 Is an index of marriages performed in the Parish Churches - it is not a Civil Registry and so will NOT include all marriages that took place during the period and area that the film covers.

0454953 Is titled Dissenters marriage index - same comments apply. Would not expect to see any births on this film, but they do get mixed up at times and not always noted correctly in the catalouge.

My understaning is that there was no legal requirement to register births before 1878. Prior to that date we have to rely heavily on the Parish Registers which is why there are so few records of non C of E persons,

From 1849 it became legal for baptisms and marriage to take place in other than the Established Church and many (all ?) from this date were also copied to the Civil Registry.

So in your period of interest, if the family were non practising C of E it is quite possible that there is no record of the births.