How to identify my G Father?

[Colkeeper]

How do I identify my Grandfather?

I have found out that his surname is not what I've always been led to believe. His name is George Norris - I don't know of any middle names and I don't know his birth or death details. He did not marry my grandmother and I've been told that he is some 12yrs her senior. He was the father of my mother and all of her subsequent siblings. My mothers birth certificate was the only one to bear his last name. I know what district of London they lived in, but no actual address. My grandmother was borne in 1886. I have used the National Archive search facility to know avail and have come to the conclusion that I have insufficient info. I'm new to genealogy research and need some advice and guidance. Can any help please!