Have you any other info?. Have been doing the search via Walter but nothing is coming up with a father George, nor with pob Edmonton. The only one is a Walter Mills born abt 1883 London living in the civil parish of Hendon at the St Vincents Roman Catholic Orphanage!
Could have Walters mother remarried and he and his siblings are under another surname on the census? His birth certificate would give you his mothers maiden name. Have you a local LDS, centre near you as they may have what you want on micro fiche, this would need to be ordered for a fee and viewed at the local LDS centre.