I love it when the wall crumbles!

I have managed to break down another wall I was banging my head against. The Walkers! My great great grandfather David Hepburn Shearer married Margaret Ann Walker in 1874. I knew her name, her fathers name and it wasn't until I found their marriage certificate uploaded to ancestry recently that I found her mothers name and her maiden name that I was able to connect more dots. Margaret Ann Walker was baptised in the church in the county of Middlesex St Giles-in-the-Fields, also commonly known as the Poets' Church, is a church in the London Borough of Camden, in the West End. Her father, Henry was listed on the baptism record as a labourer ( He was later listed on Margaret and Davids marriage certificate as a plumber.)
The next record I discovered was an immigration deposit New South Wales July 1859, which lists Margaret and her family and their ages ( Margaret was aged 9) Henry, Ann, Alfred, John, Elizabeth, Margaret and Ann's younger brother George Gray. I now have a bit of confusion, I have found another document with the family names except for Alfred on the Fitzjames in 1860, yet the immigration records were for 1859.. so more investigation to be had there! I have however managed to take the Walker and the Gray lines back another generation or two in the Buckinghamshire area.