Thanks for the information, Pat. You seem to have covered all bases. The only thing missing is the mother's full name as given on those birth certs you found in FreeBMD?

Did you find them in the 1841 census? There was a David Richardson in London, St Pancras, Queen St., aged 20, Corn agent, not born in same County (Mx), with Sophia aged 20, not b. same County, and Sophia aged 1 "Yes" (b. same County). The older Sophia's name could have been a transcription error by the enumerator.

Sue