Another marriage for you to keep on hold, needs the original record as no surname for Thomas
Thornton
Thomas 

 M MARR 17 SEP 1817 Elizabeth Cooper
Wit: John Cooper, Ann Holmes & John Geary
a ref I have has
Elizabeth   Cooper   OTP         
Thomas   Holms   OTP
AND
Dadlington   12-Dec   1825   B   
Elizabeth   Cooper   OTP            
William   Kimbrell   OTP
Been looking at this too
Leicestershire, England, Extracted Parish Records about Thomas Cooper Mary Ward
Text:    Thomas Cooper, grazier, p. Mountsorrel, & Mary Ward, lic. 11 Dec 1804
Book:    Calendar of Wills Proved and of Administrations Granted in the Commissary Court of the Peculiar and Exempt Jurisdiction of Groby, 1580-1800. (Will)
Collection:    Leicestershire: - Register of Marriages, 1560-1837
and have at last found a ref for you to chase because of the date
Sileby   11-Dec   1804   L   Mary   Ward   OTP      Spin   20+   
Of her father William Ward   Grazier
Thomas   Cooper   Mountsorrel      Bach   22   
IGI
parents:   Thos. Cooper, Mary   
name:   William Ward Cooper
gender:   Male
baptism/christening date:   04 Feb 1807
baptism/christening place:   Mount Sorrel, Leicester, Leicester, England
father's name:   Thos. Cooper
mother's name:   Mary
indexing project (batch) number:   I06824-5
system origin:   England-EASy
source film number:   1482399