Welcome to the forum, Ben.
It seems that George was actually born in Bethnal Green although his family had moved to Walthamstow by the time of the 1891 census:
https://www.ancestry.co.uk/interacti...=successSource
There is a birth registration in Bethnal Green Jul-Sep 1889 which would fit with the date of birth that you gave, since people had 6 weeks to register a birth.
This is the 1911 census entry which also gives his birthplace as Bethnal Green:
https://www.ancestry.co.uk/interacti...=successSource
Address 102 Northcote Rd, Walthamstow, and his occupation is French Polisher. This may help us to find the right military record, although unfortunately a lot of the WW1 records have not survived.