When I came to Blyth in 1983 I was posted to the Custom House, on Ridley Street.
Although no longer in use as a Custom House, the building is broadly recognisable. The building dates from 1890, and superseded the previous building on Sea View.
The old building, and indeed the whole road , has long disappeared, but I recently came across the attached photograph which shows them both. The older one was occupied by a firm of ships' agents, J Hanns & Co, who were operating from Maritime Buildings ( also long gone ) when I worked here.