Hello, Chezz,
1841 census
HO107/492 book 9 folio 20
New Road, Greenwich, Woolwich
Joseph Brown age 45 Labourer born in county Y
Sarah age 45 b in c N
Elizabeth age 23 b in c Y
William age 13 b in c Y
John age 10 b in c Y
Charles age 8 b in c Y
1851 census
Cannon Row, St. Mary's Woolwich Greenwich
Joseph Brown age 57 Lab. b Woolwich
Sarah wife age 56 n Norfolk, Yarmouth
John son age 20 Coal Porter b Woolwich
Charles son age 15 b ditto
Emily Brown niece age 2 b ditto
Charles Chapman lodger age 20 coal porter b Essex Finchingfield
As you say Joseph was on the Victory at Trafalgar & was a Greenwich Pensioner, an enquiry at the Nelson Society might yield some info as I know they do hold quite a data base of men who served with Nelson. All army pensions were paid thro' the Royal Chelsea Hospital & an enquiry there might proved useful. Also I know medals were awarded for the battle, the Nelson Soc. should be able to help there or the main PRO at Kew. The National Archives might have his records.
http://www.nelson-society.org.ukhttp://chelsea-pensioners.co.ukhttp://nationalarchives.gov.ukThese sites might help, good luck
Meliora