Hi,
Could this be your family in 1851.
HO107/1490 Folio 7 p14
Albert Powell abt 1842 Marylebone, Middlesex, England Son St Marylebone Middlesex
Charles Powell abt 1839 Marylebone, Middlesex, England Son St Marylebone Middlesex
Elizabeth Powell abt 1809 St Georges, Middlesex, England Wife St Marylebone Middlesex
Frederick Powell abt 1844 Marylebone, Middlesex, England Son St Marylebone Middlesex
John Powell abt 1811 Middlesex, England Head St Marylebone Middlesex
William Powell abt 1831 Marylebone, Middlesex, England Son St Marylebone Middlesex
Regards
Geoff