I may have the John Alfred you are seeking .. in fact there are two of them! John Afred Chalk DoB unknown, circa 1800 (son of William b.20 Jul 1769 Canterbury, Kent and Mary Vincent) m.Ann Scurr Womersley (chr. 18 Oct 1809)on the 19th Nov 1827, East Ham, Essex. Of their 5 children I have: John Alfred b. 1834
These Chalks had strong Quaker connections if that's any help to you. Womersley .. or one of them has Australian connections, in regard I believe to his humanitarian or similar interest there.