Hi,
There's John G Threlfall registered as born April-Jun 1914, mother's maiden name Gregory.
other children born from 1912 (when maiden names started to appear on registrations) of the same couple are Eunice 1912 abd Henry 1916.
Henry Threlfall married Margaret Ellen Gregory in 1899, so clearly there are other children before 1912.
in 1901 Henry aged 26, House Painter, and Margaret E aged 24 were living at 54b Botanic Rd, Southport. Both were born in Southport.
In 1911 the couple were living at 17 Windsor Rd with daughter Doris aged 4. They had been married 12 years but list only one child born in this period.
Going further back, Henry appears in the 1891 census aged 16, a house painter, son of Henry and Elizabeth Threlfall:
Henry 45 house painter
Elizabeth 44
Nancy 21 Dressmaker
Robert 19 Painter Apprentice
Henry 16 Painter Apprentice
John 14 News Boy
Jane 12
Joseph 10
George 8
I don't have any of these in my tree, though I am connected to some Threlfalls. Taking these back with the censuses should be fairly easy, but let me know if you need any more help