Re: Dunn and Blake of Portsea Island
Two main suggestions:
If you don't already have it, you should get their marriage certificate as that would give you their father's names and occupations.
There doesn't seem to be a William Henwood Dunn on the BMD indexes (looking at the images) for either April/May/June quarter or Jul/Aug/Sep quarter of 1840.There are a couple of births for 'Male' Dunn, though.
IGI does have a William Henwood Dunn, chrs. 14 JUN 1840 Saint Austell, Cornwall, England, to John Dunn and Jane.Other possiblities on the IGI to this pair are Jane Andean and Louisa.
1841 census shows, at Chtown Brick Hill, St. Austell:
John Dunn, 40, shipwright
Jane, 35, wife
William Dingle, 60, Lime Burner
All b. Cornwall.Wife may have been Jane Andean (John Luly Dunn married Jane Andean, at Mevagissey, 1 Feb 1824)