This is not the Peter from Warrington.  He was a tobacconist and died there in  1773.

Baptism records for "Deane by Bolton" and "son of John" include Peter (1734), Catherine (1737), Thomas (1740), Samuel (1744), Thomas (1745), John (1746), John (1747), Ann (1748) , Richard (1750), Betty (1751), John (1754), Mary (1755), and so on.  There must be at least two families here, but also indicate that this a Deane family (who had a Richard born 1750), cannot be the same as the Turton (Walmsley) family with brothers Peter and Richard (and possibly John & James).

The family have been shown not to be the ones of Middle Hulton, but possibly have been in Turton (or Rivington or Haslingden) for several generations. Turton Baptism records are lost for this period.

1803 or 1807 (so about 1805)

There are two Peter Mathers buried at St. Peter, with no parent shown (so probably adults), and no age.  As Peter is an uncommon name here, one of these two records is most likely our Peter.

There are no Ellen Mather buriels, that could be his wife at St. Peter.  Of the 11 burials for Ellen Mather at St. Peters, none match spouse or possible age.

Lancashire, England, Church of England Baptisms, Marriages and Burials, 1538-1812 for Peter Mather
Bishop´s Transcripts Bolton-le-Moors 1800-1809
Peter    Mather    17 Jan 1803    G.B.
Peter    Mather    19 Apr 1807    G.B.
Burial Place:    Bolton Church (for both)

Who is this Peter Mather (possibly Peter's father) ?:
Name:    Peter Mather
Burial Date:    2 Apr 1765
Parish:    Bolton-le-Moors, Lancashire, England
Register Type:    Bishops Transcripts
Reference Number:    Drm/2/19
Abode: Turton

The Peter buried at Deane who died at Little Hulton Town 3 Dec 1789 is another (he was born there too).

Ellen had children 1781 to 1788, that all died in infancy.  However it is unlikely she was much over 40 when having John, so probably born about 1745, and married 1762, when 21.

Possible Whittle, Heapey
Name:    Ellen Howarth
Baptism Date:    26 May 1745
Parish:    Heapey, Lancashire, England
Father's name:    John Howarth
Mother's name:    Mary Howarth
Register Type:    Parish Register
Reference Number:    PR 2908/1/4
Ellen dr. of John  & Mary Howarth of Whittle

Just one BIG problem: "Ellen  D. of John Howarth of Whittle" (North of Rivington) was Buried 22 October 1745.

Possibly from Blackburn, Dau of George and Ellen, bap. 28 Jun 1741.  This seems a little early for the late births, but there is one thing going for it.  George and Ellen had Ann 2 years later, so Elllen and Ann are sisters.

Also possible Livesey, Blackburn dau og George (who also has a daughter Ann)
Name:    Ellen Howarth
Baptism Date:    28 Jun 1741
Parish:    Blackburn, Lancashire, England
Father's name:    George Howarth
Mother's name:    Ellen Howarth
Register Type:    Bishops Transcripts
Reference Number:    Drb 2/6a

Possibly died 1774 (Upper Darwen) - TBC

Name:    Ellen Mather
Age:    81
Birth Date:    1737
Burial Date:    6 Dec 1818
Burial Place:    Bolton Le Moors, Lancaster
FHL Film Number:    1966408
Reference ID:    pg 189
Abode:        Great Bolton

Aged 81 ot 87 ?

Burial: 6 Dec 1818 St Peter, Bolton, Lancashire, England
Ellen Mathers -
    Age: 87 yrs
    Abode: Great Bolton
    Buried by: J. Slade, Vicar
    Register: Burials 1816 - 1820, Page 189, Entry 1506
    Source: LDS Film 1966408

Probably from Turton, (two records) confirmed by Christening record.

WILLIAM MATHER
Birth: 
Christening:  29 AUG 1762   Walmsley Presbyterian, Turton.
Christening:  29 AUG 1762   Todmorden, Lancashire.
Parents:
  Father:  PETER MATHER
  Mother:  ELLIN HOWARTH

Burial: 27 Jan 1834 St Peter, Bolton, Lancashire, England
William Mather -
    Age: 72 yrs.
    Abode: Great Bolton
    Buried by: A. Hadfield Offg. Minister
    Register: Burials 1831 - 1834, Page 268, Entry 2143
    Source: LDS Film 1966471

Three translations of this entry in FamilySearch.org.uk.

Baptisms: 24 Dec 1765 Walmsley Meeting House, Bolton le Moors, Lancashire, England
Richard Mather - Child of Peter Mather & Ellin (formerly Howarth)
    Abode: Turton
    Notes: [Congregation: Walmsley Meeting]
    Baptised by: Aspinal
    Register: Baptisms 1783-1793, Page 4
    Source: LDS Film 560904


RICHARD MATHER
Birth: 
Christening:  24 DEC 1765   Turton, Bolton Le Moors, Lancashire
Christening:  24 DEC 1765   Todmorden, Lancashire, England
Parents:
  Father:  PETER MATHER
  Mother:  ELLIN HOWARTH 


 

Richard may have been the witness to his brother Thomas's marriage to Sarah Davenport.  If so, he was still alive in 1802, aged about 37.


This could be him:
Lancashire Death indexes for the years: 1847
MATHER    Richard    92    Eastern Bolton    EB/14/29

Name:    Ellen Mather
Birth Date:    23 Dec 1771
Event Type:    Baptism
Father:    Peter Mather
Mother:    Ellen Mather
Baptism Date:    28 Dec 1771
Baptism Place:    Bolton-le-Moors, Lancaster, England
Denomination:    Presbyterian
Piece Title:    Piece 0064: Bolton-le-Moors, Bank Street (Presbyterian), 1754-1788
Abode:         Sharples

Baptism: 28 Dec 1771 Bank Street Unitarian Protestant Dissenters, Bolton, Lancashire, England
Ellen Mather - Daughter of Peter Mather & Ellen
    Born: 23 Dec 1771
    Abode: Sharples
    Baptised by: Revd. Philip Holland
    Register: Baptisms 1754 - 1788, Page 55, Entry 718
    Source: LDS Film 560877

Christening:  27 DEC 1774   Turton, Bolton Le Moors, Lancashire
Christening:  27 DEC 1774   Todmorden, Lancashire

Baptisms: 27 Dec 1774 Walmsley Meeting House, Bolton le Moors, Lancashire, England
Thomas Mather - Child of Peter Mather & Ellin (formerly Howarth)
    Abode: Turton
    Notes: [Congregation: Walmsley Meeting]
    Baptised by: Aspinal
    Register: Baptisms 1783-1793, Page 4
    Source: LDS Film 560904



 

Name:    Thomas Mather
Gender:    Male
Baptism Date:    20 Jan 1777
Baptism Place:    Over Darwen Lower Chapel Independent
Father:    Peter Mather
Mother:    Ellen
FHL Film Number:    0506876 (RG4 1020), 0506876 (RG4 882)

Abode: Bolton (possibly Turton, Bolton as baptised in Darwen)


WARNING: There is also a Thomas Mather born 9 Nov 1777, son of Abraham and Hannah Mather, baptised 11 Dec 1777 at Ainsworth Unitarian Chapel (Cockey Moor), abode Heights.

Possibly died in 1852, but the Thomas tahe was alive in Little Hulton in 1851 was born in Worsley, Manchester (near Little Hulton and Farnworth, and South of Bolton)

Lancashire Death indexes for the years: 1852
MATHER    Thomas    75    Little Hulton, Bolton    LH/4/265

Son of Peter Mather with no age given, so assumed infant

Name:    James Mather
Event Type:    Burial
Burial Date:    29 Mar 1782
Parish:    Bolton le Moors, St Peter
Parish as it Appears:    Bolton Church
Father's name:    Peter Mather
Reference Number:    L243/1/2/1
Item Number:    1
Archive Roll:    855


Burial: 29 Mar 1782 St Peter, Bolton, Lancashire, England
James Mather - Son of Peter Mather
    Abode: GB
    Source: LDS Family Search
 

Name:    Peter Mather
Event Type:    Baptism
Father:    Peter Mather
Baptism Date:    10 Nov 1783
Baptism Place:    Horwich, Lancashire, England
Denomination:    Independent
Piece Title:    Piece 3847: Horwich, Horwich New Chapel (Independent), 1751-1785

Died G.B. in Sep 1784

Burial: 13 Sep 1784 St Peter, Bolton, Lancashire, England
Peter Mather - Son of Peter Mather
    Abode: GB
    Source: LDS Family Search


Name:    Peter Mather
Event Type:    Burial
Burial Date:    13 Sep 1784
Parish:    Bolton le Moors, St Peter
Parish as it Appears:    Turton Chapel
Father's name:    Peter Mather
Reference Number:    L243/1/2/1
Item Number:    1
Archive Roll:    855

Abode:        G.B.

No age at death given, so assumed to be an infant.

Name    Margaret Mather
Event Type    Burial
Burial Date    15 Sep 1786
Parish    Bolton le Moors, St Peter
Parish as it Appears    Turton Chapel
Father's Name    Peter Mather
Mother's Name    Ellen Mather
Reference Number    L243/1/2/1
Item Number    1
Archive Roll    855

Margaret daughter of Peter & Ellen Mather of G.B.

England Deaths & Burials 1538-1991
First name(s)    Margaret
Last name    Mather
Burial date    15 Sep 1786
Burial place    Turton, Lancashire, England
Father's name(s)    Peter Mather
Mother's name(s)    Ellen Mather

No age given on burial, so assumed to be an infant death. 
This is correct and the baptism is at Rivington.

Name:    John Mather
Gender:    Male
Birth:    (blank, although others shown)
Baptism Date:    12 Apr 1788
Baptism Place:    Rivington, Lancaster, England
Father:    Peter Mather
Mother:    Ellen Howorth Mather (i.e. Ellen Howarth Mather)
FHL Film Number:    1966746

This baptism is also included in the Non-Conformist Chaple in Rivington register (see 1988 reprint of A5 booklet http://www.rivingtonchapel.org.uk/RegistersBookletLowRes.pdf)

Burial: 19 May 1789 St Peter, Bolton, Lancashire, England
John Mather - Son of Peter Mather & Ellen
    Abode: GB
    Source: LDS Family Search

England Deaths & Burials 1538-1991
First name(s)    John
Last name    Mather
Burial date    19 May 1789
Burial place    Turton, Lancashire, England
Place    Turton
Father's name(s)    Peter Mather


Name:    John Mather
Gender:    Male
Burial Date:    19 May 1789
Burial Place:    Turton, Lancashire, England
Father:    Peter Mather
Mother:    Ellen Mather
FHL Film Number:    1966744
Reference ID:    It2 Bolton May 1789
Text: "John S. of Peter & Ellen Mather of G.B."