Hi Nicola!
I'm not sure if this will help much, but I think I may have found Harry on the
1881 Census.....
Dwelling: No 3 Cambridge St
Census Place: Gloucester, Barton St Mary
PRO Ref: RG11
Piece/Folio: 2537/37
Page No: 21
Edwin Niblett Head M Male 37 Gloucester Architect
Mary E. Niblett Wife M Female 38 Coleford, Glos
Harry E. Niblett Son Male 9 Gloucester Scholar
Charles L. Niblett Son Male 8 Gloucester Scholar
Dora Niblett Dau Female 6 Gloucester Scholar
Edith Niblett Dau Female 4 Gloucester Scholar
Howard Niblett Son Male 2 Gloucester
Marie Niblett Dau Female 2m Gloucester
Katherine Martin Sister-in-Law U Female 28 Hereford Governess (TR)
FreeBMD shows that the birth of Harry Edwin R Niblett was registered in the
district of Gloucester in the Qtr to Dec 1871.
It also shows that Edwin Niblett married Mary Elizabeth Martin in the district of
Hereford in the Qtr to Dec 1870.
Hopefully, if this is the person you are looking for someone can find him on later
censuses now that you have his age and place of birth.
Best wishes,
Ju