I posted this on the epic thread but will toss it in here as well.
I found a font online called P22 Typewriter. It appears to have a 1 that matches the ‘out of place’ 1 on the Aussie BC and a lower case l that matches too.
If you visit that link and go to the ‘About this font’ tab, it will give a quick description. The last sentence says, “Additional characters were sourced from other vintage typewriters and others were designed to complete the full character set”.
Not sure which characters though...
Looks like it’s close to the different looking “1” on the Bomford B.C. However the ‘flag’ on top of the “1” doesn’t look long enough or curved enough in that example of the P22 Type.....I’ll take another look.