Margaret wasn't among the list of names that my Grandma reeled off, for her mother's eleven siblings. However, there was a girl called Alice, and this Margaret's middle initial is A, according to the census, so this could be her.
 
If it's not, there's always the possibility that this is the wrong family, but it's very accurate up to the first four children...
 
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March 2006 - update: my grandma showed me a photo of a grave stone which referred to a Margaret Alice Jones. I'm now convinced that this is the right family, as there are corresponding Margaret Alice and Evan Edward in the birth records.
Birth registered Oct, Nov, Dec 1897.
 
Apparently, Alice was engaged to William Duncan, before dying prematurely of TB. He later married her older sister, Elizabeth, and was consequently my great grandfather.
 
In 1901, she lived at 53 Rose Vale.
 
Death registered Oct, Nov, Dec 1919.
Death on grave stone: 26 Oct 1919, aged 22.
Buried in Kirkdale Cemetery.