Back to trying to sort out Eva ...
There is only one Prescott in any record who looks remotely like what we know so far.
1891 in Kings Pyon, Herefordshire
Charles Warre Prescot 52 - Justice of Peace, living on own means, born Stockport Cheshire
Mary Prescot 32
Cynric P Prescot 4
Rupert W K Prescot 2
Jane Violet Prescot 6/12
with multiple servants. More children born later. Check Cynric's and Rupert's occupation in 1911.
Rupert Warre Prescot birtn reg 1889 Weobley
Married in Bristol in 1954 and died in Lewisham in 1971.
Cynric Puleston (transcribed as Fuleston) Prescot birth reg Dec 1886 Hereford reg dist
There is no further trace of Cynric in England after 1911.
Genealogy for father Charles Warre Prescot
http://www.halhed.com/t4r/getperson.php?personID=I7259&tree=tree1(Charles's mother was born in Rugby)
"died 30 January 1922 Administration (with Will) London 28 March to Cynric Puleston Prescot captain R.C.S. Effects £18681 9s. 7d."
http://www.thepeerage.com/p31664.htm#i316639"Brigadier Cynric Puleston Prescot graduated with a Master of Arts (M.A.).1 He was invested as a Commander, Order of the British Empire (C.B.E.).1 He was registered as a Member, Institution of Civil Engineers (M.I.C.E.)."
- shows a child but no wife
http://www.thepeerage.com/p14153.htm#i141527- shows a different child but no wife
Googling his name finds military records and a book, "The chronicles of the Prescotts of Ayrefield. Compiled by Ernest Prescot Hill. Edited by Lieut.-Col. C. P. Prescot"
But I find no record of marriage or death (including in South Australia).
But aha, I have the wrong brother.
1925, birth of Rupert Warre Prescot, son of Rupert Warre Prescot and EVE SPROSTON, Norwood, SA.
There we are. Mr. Prescot. Who was evidently not married to Ms. Sproston, unless the marriage took place somewhere other than England or South Australia.
If only the newspaper reports had spelled the name correctly, I would've found them long ago.