Enumerators Instructions 1841 census (General)
'slowhands' has already answered the question re: all aged 15 on the 1841 census
read the link below which is very helpful
Instructions Enumerators 1841 census
http://home.clara.net/tirbach/HelpPage1841.html
In previous replies, a link has been given for Machen records - not covered by the Forest of Dean