3.

Elsie Margaret Blackburn-Brown (I think).

And now to Google. 

An EMBB was noted for her success at Manchester High  School for Girls, for the Joint Matriculation of the Northern Universities  - for information see this link. 

An EMBB studied at Manchester High  School for Girls. She was given a leaving present in 1914, when she left for Bedford College. Link 

An EMBB  graduated from London University (Bedford College) in 1918 with a BSc INT (Class: II) Link.  This is from the Davis Archive, a list of women who graduated in Mathematics from Universities in Britain and Ireland before 1940. 

An EMBB died in Blackburn, 18th April, 1979, a spinster. Link

That's sad. 

So, I think Elsie Blackburn Brown was born in about 1900, went to high school in Manchester, went to university in London and then became a teacher in Preston. I'm on a mission to find out now, wish me luck!