Here is a copy of a page from Jeffery's 1904-05 catalogue showing 16 and 20 bore guns that he sourced from Belgium.

Of interest is his ackowlegement that the Belgian makers could produce guns 30-40 pecent cheaper than the English, due to Belgian workers putting in a 12 hour day compared to the English working day of 7 or 8! Also, the Belgians worked for an hourly rate that was 20-30 pecent lower.

No doubt Jeffery bought from whoever was cheapest!