I have an arthur Poll that I am researching for my husband's family. I am a bit excited at finding your post and hope that you might be able to give some more information.
My Arthur Lagley Pol was born ca. 1880. On the war graves comission site, they list a Frederick Poll as his father, London, England. He was killed in France, 12 October, 1917.
Anyways, here is the story I have been told, and part of it might coincide with your story.
Oral family history tells that Arthur Langley Poll was an orphan. They say that he changed his name from De La Poll or something similar so that he could find work. Later, he imigrated to New Zealand where he married Jessie Poll(maiden name unknown), and had 8 children, the last of which is Kenneth Langley Poll, born just a year before his father was killed in the war, in France.