In the April to June 1871 birth index Walter Frederick Keyl, Marylebone, London, volume 1a, page 559.

Parish Records St. Mark, St. Marylebone, Westminster, London
Baptism May 10 1871, Walter Frederick Keyl, parents Frederick William Keyl and Sara Constance Keyl, abode 67 Carlton Hill, father is an artist

In the 1871 census 67 Carlton Hill, Marylebone, London
Head Frederick W. Keyl, age 47, artist, painter, born Germany
Wife Sara C. Keyl, age 40, born India
Son Norman Keyl, age 4, born London
Daughter Frances M. Keyl, age 2, born London
Son Baby Keyl, age 1 month [or perhaps week], born London
Daughter Henrietta Keyl, age 16, scholar, born London
Aunt Elizabeth Woodin, age 73, independent, born India
3 servants
[It would seem Elizabeth is Sara’s aunt. Sara Constance Woodin (daughter of William Woodin, merchant) married Frederick William Keyl in 1852 ]

In the 1881 Census Belge?, High Street, Brading, Hampshire
Sara C. Keyl, widow, age 48, born East Indies
Son Walter F. Keyl, age 10, scholar, born London
1 servant

In the 1891 census Grosmont, Brading, Isle of Wight, Hampshire
Head Edwin B. Keyl, married, age 28, living on own means, born Marylebone, London
Wife Eleanor J. Keyl, married, age 33 living on own means, born Scotland
Brother Walter F. Keyl, single, age 20, living on own means, born Marylebone, London
1 servant