Thanks for the PM, Gill
For others trying to help in this one, the main points are:
1891 - RG12 60 74 38
William age 6 with parents William and Eliza
1901 - RG13 78 16 23
parents and siblings, William left home.
witnesses on marriage - Bertie W (appears to be brother, as is on 1901 census,)
and Eliza Mary (appears to be mother)
Father stated to be William Coote, painter, deceased.