Hi,
first of all, the census query, under the age of 1, the age is usually 2/12 or 8/12.
The Ireland record is correct, there wasn't an Evelyn Rumsey with or without a middle name born between 1908 and 1915 in the UK. So it is the Ireland one. Possibly you have the date she arrived in England or her Baptism date, you would need to get the official birth record as this is the only record of a Rumsey born to a Higgins other than the boy you will find later further down this page.
I searched for George Higgins the uncle to his previous census records to find his sister as I didn't know her name or Evelyn's fathers name. That's how I got Lucy.
There are 2 George Albert Rumsey one born in 1870 (another name William) and the other 1879 (other name Robinson) which is yours. They may be related going back some years, check the census and you will see them.
Leonard George Rumsey, he died 26th December 1925 and left £75.00 to George Rumsey a Grocer.
At that time he lived at 20 Clovelly Road, Portsmouth.
You may have heard of Spike Milligan b 1918 in India, I don't know the cut off date but, the British changed the policy on birth rights for Forces Births. If you were born to a serving person in another country overseas you were registered as British, when they changed the policy you had to register in the country of the Fathers Birth, so Spike became Irish, though he didn't mind.
So with Evelyn being born after Leonard, the father may have been posted to Ireland from India and registered her there. As I say I don't know the cut off date, but with her being born there she was still British.
So, where to next......the Army Papers, They are not listed in the site I got the info from so you would have to contact Kew in London to get a copy and this would tell you all the story.
Anyway, please read below and I hope this has helped.
Maggsie
Marriage Of Lucy Mary Higgins and George Albert Rumsey
in the Year 1903 Jul-Aug-Sep qtr
district of Elham in Kent
Volume 2a Page 2257
George Albert Rumsey
I must add...... Pembrokeshire is in Wales.