There are various births on freebmd that we might speculate about, especially those with Amy, Herbert Harry or Henry in the first name. Unfortunately they are born before 1811, so we couldn't be sure without purchasing the certificate.
I couldn't find any with a variation of Poyntz as a first or middle name.
Any children might be rather young for WWI, but you could try the CWGC site just in case. Other than that I think it might be electoral registers.
I am a bit stumped!!
A
p.s. Oh you could check for deaths to see which area they lived in.
