Repairing a Russell Hobbs Bread Maker?

Some kind person has donated a broken bread machine to a charity store instead of getting rid of it. My partner and I bought it and our excitement to bake has soured somewhat.

I don't really want to have to take it back to the charity store as its money is going to a good cause. Taking it to a repair shop is more than the machine is worth (I'm sure the old owner knew this).

I'm quite annoyed they would donate a broken machine so the most wholesome way to get revenge would be by fixing it!!

It's a RHBM1500. It has two paddles at the base which knead the dough. (you can see them here https://youtu.be/wGsn-uj-doY). One of the paddles doesn't knead the dough. Underneath the bread tin, when you take it out is a metal base plate, with two rotating apparatuses which turn the paddles in the bread tin. One is stiff to turn and quite stable and this one works perfectly. The other spins very easily by hand, offering no resistance. We think it is slightly raised and not quite as stable. This is what is broken I think.

Any ideas how to fix? I plan to get a screwdriver tomorrow, take the base plate off and check the belt situation. Any idea on other problems outside of the belt, as to why the apparatus turns so easily, but won't be spun by the machine?

Thanks so much!