One idea I had to try to locate my great great grandfather, Walter Fordham Cox, was to attempt to track all females whose maiden name was Fordham, born only in the West Ham registration district from 1860 to 1870 through to the 1891 census.
My aim here was to discover if any of them had a child living with them whose birth had not been registered as expected; my thinking that any children living with them whose births had not been registered were possible candidates for Walter Fordham Cox. (A possible nephew of one of these.)
Having now completed this, unfortunately I have to say that I did not discover Walter in any of the households of the 6 females I was able to trace to the 1891 census. A further 3 females died as young children. While there were also births of 4 males caled Fordham during this period, I did not attempt to trace the males further in this excercise.