It looks as though Charles Porter may in fact have been born in Lawford, Essex in 1838 (parents Jasper, also a chimney sweep, & Susanna) & that the family had moved to Manningtree by 1851.
If so it may be that a Lawford birthplace, rather than Manningtree, appears in some records.
This Charles is still with parents in 1861 as an unmarried fisherman.
1871 at "Quay", Manningtree: he's a fisherman, 32 b Lawford. Wife Elizabeth is 24 b Dedham. Children are Elizabeth 6, Charles 5, Minnie 2, Lucy 1mo.