IGI Individual Record Family Search International Genealogical Index v5.0 British Isles
JOHN REDMAN Christening:  24 DEC 1810 Haworth, Yorkshire, England Parents: Father:  WILLIAM REDMAN 
Source Information:Batch No.: C018513 Dates: 1726 - 1812 Source Call No.: 0990541 Type: Film Printout Call No.:  6909899  

John's name on his marriage entry from Cloughton, Yorkshire spelled as Readman.

I cannot find the family on the 1841 census for England, would this mean they were already in Canada?

On the 1851 census for East Garafraxa Township there are 2 children listed that are not in the file at this time.  The first is a female but I cannot make out the name, she is 9 years of age so would have been born about 1842. There is also a Mary aged 4, born about 1847.  Did this child die at a young age and they had another girl born named the same in 1857?
1851 Census of Canada East, Canada West, New Brunswick, and Nova Scotia about John Redman 
Name: John Redman Gender: Male Age: 44 Estimated Birth Year: abt 1808 Birthplace: England Province: Canada West (Ontario) District: Wellington County District Number: 39 Sub-District: Garafraxa Sub-District Number: 371 Page: 1 Line: 17 Roll: C_11756 Schedule: A

On the 1851 census for the Twp of Falsgrave in Yorkshire England there is a William Readman, aged 67 born Eglou, Yorkshire and  his wife Hannah, aged 67 born in Hawsher.  Could these people be John's parents?

The British Constitution Fergus Freeholder & North Wellington General Advertiser, Friday, June 1, 1866 edition had the following write up.  John Redman of Garafraxa hung himself with a pail hoop thrown over a wooden peg in the wall on Saturday last.

The transcript of the McKee Pioneer Cemetery, REDMAN In memory of Christina, wife of John Redman.  Died June 25, 1890, aged 81 years.  Wm Redman, died Feb. 13, 1904, aged 67 years.  In memory of John Redman, died May 26, 1866, aged 66 years.  George, son of J. & C. Redman, died Aug. 22, 1873, aged 20 years, 1 month, 18 days.