In 1926 George H Day was living at
Durden Dene,
Crabtree Lane, Harpenden, and was in
Crabtree Lane (no house name given) in 1912 - according to the Kelly's Directory for Hertfordshire. This suggests you should be able to find George in the 1911 Census,and if you look at the censuses on Ancestry you will find many people called Day being born and living in Harpenden for most of the relevant period. This suggests that a normal search of the censuses, FreeBMD, etc., could establish a link.
I noted in 1901 George Day (58, Brickyard
Foreman, born Harpenden) who was on West Common, Harpenden, Near Hatchen Green Farm. He is the right age to be the brother (or cousin) of the William Day mentioned before in this thread (and see under "Day" on www,hertfordshire-genealogy.co.uk). I suspect that this George Day may have worked for William
Atherton Smith (a farmer who also made bricks, and my great great uncle) and if you track down the family relationships from the census, etc., I might be able to find out a bit more about him.