I may have found William and Ellen in the 1901 but the birthplace is not Bethnal Green, I don't know England very well so I have no idea where Bow is in relation.
William McEwen Head 30 b London Bow French Polisher
Ellen Wife 28 b London Shoreditch
Ellen Daughter 8 b Essex Westow
Elsie Daughter 2 b Essex Westow
Address looks like: 88 Higham Street
Walthamstow, parish of St John, Essex
RG13/1631/94 p 50 schedule 308
ED 56 RD West Ham SD Walthamstow