Hi Cheryl
How sure can you be that Harry grew up in Margate and/or that he was born in Margate or Canterbury? Have you looked at the 1911 census
http://www.1911census.co.uk/ - you will need to purchase credits to see the actual details but, as I said, (and assuming I have the correct family) it says Harry COX age 29 in the Islington district of London and I went through all the counties and he doesn't show up until I entered born "Northamptonshire" and then I tried born "Warmington" like the 1891 census entry above and up he pops

Try using the full person search for Gladys COX born Margate and up pops Gladys Margaret COX in Islington born Margate. The try COX in Islington with (other member of household) Gladys Margaret COX and you will see Beatrice 30, Harry 29, Henry George 1. Then search for Harry COX age 29 in Islington born Kent - he doesn't appear and he won't appear until you type in born Northamptonshire and/or Warmington

In the 1901 census his father appears to be a carter too ...............
35 High Street, Higham Ferrers, Northamptonshire
George COX head mar 46 carting contractor b.(L?)uton Northamptonshire
Sarah Ann wife 46 b.Warmington
Geo. son unm 20 shoe finisher b.Elton
Charles son 16 cart man b.Newton Bromshold
Mabel dau 13 b.Higham Ferrers
Arthur son 10 b.Higham Ferrers
Ethel dau 8 b.Higham Ferrers
Edith?? dau 5 b.Higham Ferrers
Ed. WEATHERINGTON boarder unm 36 brickyard lab b.Warmington
Charles WEST lodger wid 61 ?? b.Hull Yorkshire
Albert WOOD lodger unm 18 cart man b.Lavender Buckinghamshire
Walter HOLM(??) lodger unm 20 cart man b.Wolleston Northamptonshire
RG13/1440 folio 6 page 4
Casalguidi
