Things are going well - I managed to get the balance wheel off! But I rethought what I'd written above about the engraving on the needle plate. I don't think the number is a part number - that probably came later with big factories like Singer. I think it's the *serial number*! Number 418 - that was probably its production number.
And I checked with Google Maps - Perth is actually almost 50 miles from where I live, in Ottawa. But it's only about *5* miles from where I found Venus, in Balderson. So it looks like this little machine was bought locally and never left the area where it was built. I like these little details; it feels like peeking into the actual life of the people who used these machines.