Hi Stuck
Could this be your Arthur in 1901? I know it's his brother who is the Edmond , but after lots of different searches he is the only possible match I found.  The Walts looks like Watts to me on the original image.  

 Jan
Arthur E Walts, 7,Son, born Paddington, London, England        
Laburnum Cottage, Gordon Ave
Harrow Weald, Middlesex
RG13/1210 Folio 80   
Arthur E Walts     7     Paddington, London, England     Son     Harrow Weald     Middlesex     
Edmund A Walts    8    Paddington, London, England    Son    Harrow Weald    Middlesex    
Edward R Walts    32    Marylebone, London, England    Head    Harrow Weald    Middlesex    Plumber
Elizabeth S Walts    29    Mentmore, Buckinghamshire, England    Wife    Harrow Weald    Middlesex    
Ellen M Walts    3    Harrow Weald, Middlesex, England    Daughter    Harrow Weald    Middlesex