Aged 45 in 1841
Aged 55 in 1851
Aged 66 in 1861, Born Tattenhall
Aged 74 in 1866 (when died, registered Tattenhall)

Probably the son of Thomas Hopley (living with him in 1841, aged 80)

William or Mary or transcription error?  There is no Mary, daughter of Thomas and Jane baptised 25 July 1789 at Malpas (on either the Bishop's transcript oo the Malpas index).  The only HOPLEY baptism is for William on the 28th July 1789:

Name:     William Hopley
Event Type:     Christening
Event Date:     28 Jul 1789
Event Place:     Malpas, Cheshire, England
Father's Name:    Thomas Hopley
Mother's Name:    Jane
GS Film number:    2068452
Digital Folder Number:    004011477
Image Number:     00084

William son of Thomas & Jane Hopley of Macefen (see image)

There is also a William, son of William and Sarah, born Malpas in 1791.

Cheshire Death indexes for the years: 1866
HOPLEY    William    74    Tattenhall    Cheshire West    TAT/9/1

Both William and wife Ann's deaths are registered at Tattenhall, so the age is probably correct.

Aged 50 in 1841
Aged 60 in 1851, born Holt
Aged 75 in 1861, born Holt

Name:    Ann Axon
Gender:    Female
Baptism Date:    7 Mar 1786
Baptism Place:    Holt, Denbigh, Wales
Father:    John Axon
Mother:    Mary
FHL Film Number:    1655830

Cheshire Death indexes for the years: 1868
HOPLEY    Ann    81    Tattenhall    Cheshire West    TAT/9/58

John was 19 in 1841

John assumed to have been born at Holt where his closest brother Thomas was born

Name:    John Hopley
Gender:    Male
Baptism Date:    25 Dec 1821
Baptism Place:    Holt, Denbigh, Wales
Father:    William Hopley
Mother:    Ann
FHL Film Number:    1655830

Thomas was 27 in 1851, born at Holt (like his mother)

Name:    Thomas Hopley
Gender:    Male
Baptism Date:    14 Mar 1824
Baptism Place:    Holt, Denbigh, Wales
Father:    William Hopley
Mother:    Ann
FHL Film Number:    1655830

Aged 24 in 1851, Born at Chester Barton.

"Chester Barton" is Barton, Cheshire.  Barton is 2 mile West of Broston and Barnhill is one mile East of Broxton where the family farmed in 1851.

Name:    William Hopley
Gender:    Male
Baptism Date:    17 Jul 1826
Baptism Place:    Farndon, Cheshire, England
Father:    William Hopley
Mother:    Anne
FHL Film Number:    1655669

21 in 1851, born Chester Barton

"Chester Barton" is Barton, Cheshire.  Barton is 2 mile West of Broston and Barnhill is one mile East of Broxton where the family farmed in 1851.

Name:    Randal Hopley
Gender:    Male
Baptism Date:    4 Jan 1830
Baptism Place:    Farndon, Cheshire, England
Father:    William Hopley
Mother:    Anne
FHL Film Number:    1655669