Another child of theirs? Francis Burdett son of John Miller Brickr & Rebeca born 1 Sep and baptised 4 Nov 1804 at St Giles Cripplegate:
https://www.ancestry.co.uk/interacti...&usePUBJs=true
He was mistranscribed on Ancestry as having surname Burdett but I am putting in a correction (I found him on a public tree but it had no info about what happened to Rebecca).