Jomot1 - I'd already had no luck searching for a birth for John Gilroy Phillips, and then once I started looking for Septima I just knew it was going to evolve into one of those really messy families. :biggrin:
I found actually found Septima's death and birth registrations easily, as well as her 1881 census entry.
Even using the date of birth in the 1939 Register, I found no trace of a birth registration for Marie L Phillips.
I did find a Septima Sarah Susan Phillips living in Tyron Street, Chelsea in the electoral roll for 1933.
Also in the same houshold were Charles Alfred Phillips and Philip Duncan Phillips.
The latter must be the Duncan Phillips who's aged 1 in the 1911 census (your post #7), and the Philip born 1910 in the 1921 census. (your post #8) No wonder I couldn't find a birth registration for Philip Duncan Phillips. Couldn't you just throttle some people!!
And I know I'm doing this back to front, but a year earlier, 1932, electoral roll. Tyron Street, Chelse.
Septima Sarah Susan Phillips, with Charles Alfred Phillips, Donald Arthur Phillips, and Philip Duncan Phillips.
1928 electoral roll
City of London -8 Addle Hill London E.C.4. - Septima Sarah Susan Phillips (abode 88 Lewisham High Rd, S.E.)
1929 electoral roll
44 Broadwall, Lambeth S.E.1. - John Gilroy Phillips and Septima Sarah Susan Phillips.
Also in the same house was Alice Clifton.