Possibly the same, or perhaps the father of, the John Langford, described as a Goldsmith and Jeweller from London, that arrived in Halifax, Nova Scotia, shortly before September 1809.
The John Langford from London was married to Grace, and father of the Nova Scotia silversmith, James J. Langford.
Following the death of John Langford, sometime after 1815, Grace remarried again, this time to the Nova Scotia Silversmith, Peter Nordbeck.
See James J. Langford at page three of: The Canadian Trade, Information, Advertisements, Etc.