Hi MissHaley,
It maybe worth posting in the Canadian bit of this site with your query too and posting a link to this thread within your post.
I don't know anything about Canadian Marriage certs, but if the information on a Canadian cert gives the parent (s) name, I think that your first step would be to acquire/purchase your grandfather's marriage cert( If he married in Canada) It would make your search for his birth in the UK a lot easier, plus when you find a birth you'll know it will be the right one by matching his parent or parents from his marriage cert.
I have looked for his birth in the BMD indexes for England and Wales (both on ancestry
http://home.ancestry.co.uk/ and Free Bmd
http://www.freebmd.org.uk/cgi/search.pl). There doesn't seem to be any Russell Denson birth registered in England around 1913 i. I have tried it with a wildcard search of Russel* and Den* to allow for misspellings )
Are you sure it was his first name, and Russell wasn't a middle name that he was just known by?
Do you know when his brother Alfred was born? If he is older than your grandfather there are a few possibilities in the England census for Alfred. There is one born in London abt 1897 and living in London with a widowed father and an older brother Thomas in the early 1900's. Father's name Robert Jackson Denson
Did Alfred have a middle name? Do you know of anymore siblings?
Do you know what time frame they emigrated to Canada? Did they emigrate as children or when they were adults? Did they emigrate when they were single or married? If when married , you can search for a marriage in the England and Wales BMD indexes. By purchasing his marriage cert from the GRO of England and Wales , it will give you his father's name if known. and the occupation of his father, plus any witnesses (who sometimes turn out to be family)
All info helps
I guess you have seen this on findagrave?
Birth: 1913
Death: 1984
http://www.findagrave.com/cgi-bin/fg.cgi?page=gr&GRid=127540190&ref=acomIs this him in the voters lists?
1968
38th street Close:
Russell Denson
Occupation: Kitchen Helper
Location:Red Deer, Alberta, Canada
1974
35th street
Russell Denson
Occupation:Cleaning Porter -
Location:
Red Deer, Alberta, Canada
Don't know if this is the same man, but will post it anyway:
1949
Ponoka
Russell Denson
Occupation:Farmer
Location:
Wetaskiwin, Alberta, Canada
Kind Regards