To answer your questions:
Where did you get the film? It came in a box of Lomography 400 film of which one was gone. Sealed in the individual paper holder. I have a second one too 😎
Does the camera have two winder wheels and does it wind either way? Nope!
Are you sure there is film on the back of that paper roll? Nope!
Or could it be that you have only the paper roll of without any film attached, rewound on the wrong way? Could be!
"... so I suspect you probably know what this film mystery is all about" - I honestly don't! It's my first roll of 120 film EVER and so that explains why it took me ages to figure out how I had to wind it on quite a lot further than I expected to get to the numbers and the dots. I don't think it in any way explains why everything is upside down though UNLESS....
maybe this was stock meant for south of the equator???????????? 😱 Am I shooting with Aussie bound 400 film?
Anyway, the weather has been crap so I haven't got past frame 4 yet. If it will help you sleep better I'll shoot random stuff just so we can get the film on its way to the developer 😀
Just for the record, the 3 and 4 are the the same orientation.
Now what's the chances the second roll will be the same? Only time will tell.
Okay, you've vindicated yourself. Moving on...
Down here on the big isle of kangaroos and koalas we have a lot of filmless paper backing films - not saying these are sold on Ebay, but not saying they aren't either.
For us Ozzys film of any sort, even with odd Chinese or Russian hieroglyphs on their paper backings, is do expensive, many poverty-stricken shooters (I fit into this category) in their/own desperation often reload respooled filmless paper backings in their ancient instruments and go out let's-pretend shooting, something to do during these Covid times.
To end all this and bring it to some sort of sensible conclusion, when you eventually finish the roll, film or no film, get it processed (what! you don't do your own at home?) and let us know the results. Better yet, post a few more photos.
Finishing up with some practical advice - Mike Butkus's excellent camera manuals site will surely provide you with a manual for your camera. Yo'll enjoy reading it. I've downloaded a few and reread them regularly - often as not they clear up many small problems I have when I take out a camera I've not used for some time and find I've forgotten many of the basics.
Send him a small donation via Paypal for your download. Mike is an excellent resource and needs to be encouraged to keep on keeping on.
Looking forward to seeing your first roll photos when you get them back from the lab.