In 1778 John married a Widow so he was probably about 30 (or older), but just a guess.  They has two children at Little Hulton, again suggesting early thirties and probably born Little Hulton.  John son of John from Little Hulton, born 1764 is therefore a good match.

Name:    John Mather
Event Type:    Baptism
Baptism Date:    5 Nov 1746
Baptism Place:    Deane, St Mary, Lancashire, England
Father:    John Mather
Reference Number:    GB127.L85/1/1/2

First Bap. of Novermber (3rd or 5th maybe)
John son of John Mather of Little Hulton

There is also a bptiism 30 Dec 1847 at Deane for "John, son of John Mather of  Great Bolton", so John may had died and another one baptised a year later, although there is bo burial record.

Name:    Betty Mather
Event Type:    Baptism
Baptism Date:    18 Jun 1779
Baptism Place:    Deane, St Mary, Lancashire, England
Father:    John Mather
Mother:    Mary Mather
Reference Number:    GB127.L85/1/1/2

Abode: Little Hulton

Name:    Jno Mather
Event Type:    Baptism
Baptism Date:    3 Jun 1781
Baptism Place:    Deane, St Mary, Lancashire, England
Father:    Jno Mather
Mother:    Mary Mather
Reference Number:    GB127.L85/1/1/2

Abode: Little Hulton