I just spent a few minutes composing a reply and then the skies opened in my world & a massive storm hit - managed to lose the adsl link and my message
you can find your family in 1841. (apologies if you already have). I searched for Richard. The family is at Gwennap and there is no sign of Baby John, so either he died or was not born before the census. It could be that the later children were not baptised.
Have you found any of them in 1851? This may give a clue if they were born elsewhere.
Thank you for looking but yes I did find the family in the 1841 Census at Gwennap, but I am trying to track down their births/baptism dates now - I found Grace & Ann in Gwennap but the other children were not baptised there, will look at other villages close to Gwennap.