Hi
Here are your definites - I will have another scout around on the 1841 and get back to you with possibles. Do you need Maria on the 41 as well?
Cheers Jan

1851
Letcomb Bassett
William Carter Head Mar 25 Ag Lab Wantage
Maria do Wife 21 Letcomb Bassett
Isaac do Son 3 Scholar do do
William do do 1 do do
HO107/1689/131 Pg9
1861
Letcomb Bassett
William Carter Head M 34 Shepherd Wantage
Maria do Wife 30 Letcomb Basset
Isaac do Son 13 Plough boy do do
William do Son 11 do do do do
Mary do Dau 9 Scholar do do
Albert do Son 6 Labr Son do do
James do do 4 do do
Amelia do Dau 1 do do
RG9/735/107 Pg36/37
1871
Letcomb Bassett
William Carter Head M 43 Ag Lab Wantage
Maria do Wife 41 Letcomb Bassett
Albert do Son 18 Ag Lab do do
James do do 14 do do do do
Amelia do dau 11 do do
Eli do Son 2 do do
RG10/1268/16 Pg23
1881
Hill Barn Letcombe Bassett
Wiliam Carter Head M 55 Shepherd Wantage
Maria do Wife 51 Letcomb Bassett
Eli do Son 12 do do
RG11/1288/13 Pg20
1891
Downs Cott Sparsholt
William Carter Head M 65 Shepherd Wantage
Maria do Wife 61 Letcombe Bassett
Mary Cousins Dau M 39 do do
RG12/982/105 Pg8
I can't see either of them in 1901.