Hello folks! This is not my bike nor do I know the owner, but someone over on the Rivendell list posted looking for info regarding the particular model.
Defining characteristics (as passed onto me) are the twin top tube, 3-speed hub, full generator lighting, factory rack, seat bag, chrome fenders.
The closest thing that resembles it is a Mountie. Here is the page from the 1967 US catalogue.
The Mountie was a 20″ wheeled bike, but the extant bike in question is 26″. And in the catalog the Mountie was a single-speed/coaster braked model, whereas the mystery one has caliper brakes and a S-A three-speed hub.
Here are the photos.
Anyone have any guesses?