1851 Census Amos is under MANKTELOW on Census.
He is with Mother Avis, a Labourers Widow, born c 1781, Withiham, Sussex.
They are living in Speldhurst, Kent.
1841 Census
Speldhurst, Kent
HO107/462/4/Speldhurst
Avis MANCKELLOW, 57, Charwoman
James, 18, Ag Lab
AMOS, 14
All NOT born in County
Looks like they had a mass Christening in Sussex;
16 June 1828, Rotherfield, Sussex to JAMES/AVIS
All Christened same date, Birth dates next to names;
JOHN GEORGE, 11 Sept 1816
HARRIET, 30 Dec 1817
JAMES, 11 Feb 1822
PHOEBE, 28 July 1824
AMOS, 20 May 1827****
MARY, 25 May 1820
(Familysearch.Org)