I found Lettice's baptism record showing she was born on 13 January 1836 to William Lloyd and Anne Lewis in Llangendeirne.
On her baptism father William occupation farmer
Lettice Lloyd
Birth Date 13 Jan 1836 Llangendeirne, Carmarthenshire, Wales
Baptism 20 Mar 1836 Abergwilly, Carmarthenshire, Wales
Denomination Calvinistic Methodist
Father Wm Lloyd Mother Anne Lewis
I can’t find a marriage to David Harris
Nor can I find the family on 1861 census - Perhaps they didn’t marry ?
Is this Lettice on 1851 census?
Lettice Lloyd Age 16 born Llangendeirne, Carmarthenshire, Wales, servant
Civil Parish or Township Llandefeilog
Town Scyborfawr Carmarthenshire
Sub-registration district Llangendeirne
Piece 2472
Folio 305
Page number 14
Have you seen this 1881 census entry could this be Lettice with her mother ?
Lettuce Davies Age 45 born Llangendeirne, Carmarthenshire, Wales
Civil parish Llanelly
Street Address 28 Panteg Row
Condition as to marriage Married
Piece 5375
Folio 92
Page number 7
Household Members
David Davies 48 Head occ Railway (Ry Lab)
Ann Lloyd 79 Mother in Law Llandyfeilog, Carmarthenshire
Looks as if they married 1860
Letitia Lloyd age 21
Marriage 26 Oct 1860 St Trinity Church Felinfoel Llanelly
Father William Lloyd , farmerSpouse David Davies 21 cc block layer father Daniel, gardener
Both made their mark, abode Felinfoel