George was a weaver when Hannah and Susannah were baptised and a labourer again in 1837 when Thomas  baptised

Labourer at Hullot Hall when Thomas was baptised and for 1841 census (Civiger)

Jane Slater was 13 in 1841
Jane Slater was 23 in 1851
Jane Hargreaves was 33 in 1861

Aged 11 in 1841

Name:    Hannah Slater
Birth Date:    19 Sep 1829
Gender:    Female
Event Type:    Baptism
Father:    George Slater
Mother:    Sarah Whithead
Baptism Date:    13 Oct 1829
Baptism Place:    Merclough, Lancaster, England
Denomination:    Wesleyan
Piece Title:    Piece 1489: Merclough, Parish of Whalley (Wesleyan), 1823-1837

Hannah the daughter of George Slater of Scholeyhead in the parish of Whalley in the county of Lancaster, Weaver and of Sarah his wife who was the daughter of William and Nancy Whitehead ...

Today, Scholey Head Lane heads East off Red Lees Road, midway between Mereclough and Cliviger.

Aged 8 in 1841

Aged 5 in 1841
Aged 16 in 1851
Aged 26 in 1861
Aged 46 in 1881, born Merclough

Name:    Swsanna (Susannah) Slater
Birth Date:    23 Aug 1834
Gender:    Female
Event Type:    Baptism
Father:    George Slater
Mother:    Sarah Whitehead
Baptism Date:    15 Sep 1834
Baptism Place:    Merclough, Lancaster, England
Denomination:    Wesleyan
Piece Title:    Piece 1489: Merclough, Parish of Whalley (Wesleyan), 1823-1837

Susannah the daughter of George Slater of Scholey head in the parish of Whalley in the county of Lancaster, Weaver and of Sarah his wife who was the daughter of William and Nancy Whitehead ...

Today, Scholey Head Lane heads East off Red Lees Road, midway between Mereclough and Cliviger.  The modern name is Over Town.

Name:    Susannah Hargreaves
Estimated Birth Year:    abt 1835
Registration Year:    1900
Registration Quarter:    Apr-May-Jun
Age at Death:    65
Registration district:    Burnley, Lancashire
Volume:    8e
Page:    178

3 in 1841

Name:    Thomas Slater
Birth Date:    14 Jan 1837
Gender:    Male
Event Type:    Baptism
Father:    George Slater
Mother:    Sarah Whitchead
Baptism Date:    21 Mar 1837
Baptism Place:    Merclough, Lancaster, England
Denomination:    Wesleyan
Piece Title:    Piece 1489: Merclough, Parish of Whalley (Wesleyan), 1823-1837

Thomas the son of George Slater of Hullot Hall in the parish of Whalley in the county of Lancaster, Labourer and of Sarah his wife who was the daughter of William and Nancy Whitehead ...

Today, Scholey Head Lane heads East off Red Lees Road, midway between Mereclough and Cliviger.  Hullot Hall was probably at nearby Pickup Bank.  The family were still at Southward Bottom (less than a mile SE of Cliviger) in 1841.

SLATER, JOHN        WHITEHEAD 
GRO Reference: 1840  S Quarter in THE BURNLEY UNION 
Volume 21  Page 184

    SLATER, JOHN        1 
GRO Reference: 1841  D Quarter in THE BURNLEY UNION  Volume 21  Page 117

SLATER, BENJAMIN        WHITEHEAD 
GRO Reference: 1844  S Quarter in THE BURNLEY UNION 
Volume 21  Page 224

SLATER, BENJAMIN        0 
GRO Reference: 1845  J Quarter in THE BURNLEY UNION 
Volume 21  Page 139