All from this site,

On the assumption that this is Warren JAMES’s parentage,

Record ID 40659
Entry Number 656
Year 1792
Month Jul
Day 29
Parents Surname JAMES
Child Forenames Warron
Fathers Forenames Warron
Mothers Forenames Ann
Mothers Surname
Residence
Occupation
Officiating Minister
Event Baptism
Memoranda son of
Notes
Register Reference P57 IN 1/1
Page Number 123
Parish Chapel Bream

Record ID 148653
Entry Number
Year 1777
Month Jun
Day 6
Grooms Surname JAMES
Grooms Forenames Warren
Grooms Age
Groom Condition
Grooms Occupation
Grooms Residence Newland
Grooms Fathers Surname
Grooms Fathers Forenames
Grooms Fathers Occupation
Brides Surname KEAR
Brides Forenames Anne
Brides Age
Brides Condition
Brides Occupation
Brides Residence Newland
Brides Fathers Surname
Brides Fathers Forenames
Brides Fathers Occupation
Licence or Banns Banns
Date of Banns
Signature or Mark He signs she marks
Witness 1 Dorothy Tyler
Witness 2 R Williams
Other Witnesses
Officiating Minister P Ball vicar
Event Marriage
Memoranda
Notes
Register Reference P227 IN 1/7
Page Number 508
Parish Chapel Newland

Assuming that Warren James the Elder might have been born ca 1755,

Record ID 40017
Entry Number 16
Year 1751
Month Nov
Day 10
Parents Surname JAMES
Child Forenames Warren
Fathers Forenames Richard
Mothers Forenames Sarah
Mothers Surname
Residence
Occupation
Officiating Minister
Event Baptism
Memoranda son of
Notes Any abbreviated forenames have been expanded to the full name
Register Reference P57 IN 1/1
Page Number 3
Parish Chapel Bream

We might therefore be looking for a brother named Jeptha born reasonably close to this,

Record ID 389401
Entry Number
Year 1755
Month Sep
Day 21
Parents Surname JAMES
Child Forenames Jephthah
Fathers Forenames Rich[ar]d
Mothers Forenames Sarah
Mothers Surname
Residence Breem
Occupation
Officiating Minister
Event Baptism
Memoranda
Notes
Register Reference P227 IN 4/1
Page Number 271
Parish Chapel Newland

Since Bream was a Chapelry of Newland baptisms could be recorded in both places. Interestingly enough the latter record appears at Bream under the name Japeath,

Record ID 40074
Entry Number 72
Year 1755
Month Sep
Day 21
Parents Surname JAMES
Child Forenames Japeath (transcription is correct - Ancestry image)
Fathers Forenames Richard
Mothers Forenames Sarah
Mothers Surname
Residence
Occupation
Officiating Minister
Event Baptism
Memoranda son of
Notes
Register Reference P57 IN 1/1
Page Number 11
Parish Chapel Bream

Later note.Does the mentioned book imply that Japeath/Jeptha was alive at the time of the riots? If so this post may be a red herring.

Warren’s sister may be worth following up as evidenced by this newspaper comment during a report of the riots and his part in them,

BNA Cheltenham Journal and Gloucestershire Fashionable Weekly Gazette. - Monday 27 June 1831

The Foresters quoted the Duke of Beaufort and the Lord Chancellor, as authorising their conduct! His Grace is stated to have recommended them to petition, and merely promised to support their prayer. Warren James's sister lives as servant to the Lord Chancellor, whom he pretends to have consulted. The soldiers found out his signals, three claps of the hand, which brought him up from the mine, and placed him safe in their clutches. Like all English and Irish mobs, the Forest Rioters are great cowards.