Hi MMC52B,
Welcome to Rootschat

1901 Census has Louisa and William born WEST Ham, Essex
If you search
www.freebmd.org.uk there are few possible marriages for William post 1915. Two are under William.A. including these;
William. A. GRAHAM;
March 1917 to Louisa.J.M. HOOPER
December 1824 to Florence.M.CLEMENTS
Ring a bell?
Sorry cant help with descendants. I cant find anyone researching this Family on Ancestry.
Trish

The only birth of a child I can find in Essex is;
Female GRAHAM, December 1925, Edmonton, 3a 754
Mothers name Clements
These are out of Essex;
GRAHAM/Mothers name HOOPER
LILY, March 1915, Kensington, 1a 167
ROSE, March 1915, Kensington, 1a 166 ( TWINS?)
WINIFRED, June 1920, Kensington, 1a 184
There could be others but index does not go past a certain year.