I agree with you 110% about chucking stuff away.
I'm guessing the broken/missing "bushing" on your tool is a sort of "dull golden/copper/slightly speckled" colour? In which case it's not "just" a bushing, it's a bearing too (probably for one end of the motor shaft). In that case, YES it definitely DOES matter and you MUST use Phosphor Bronze, NOT steel. The reason is that P-B is slightly "spongy", is pre-soaked in oil before factory assembly, and being spongy, it holds that oil for a long long time. So you need the same material.
If you've found that official B&D spares are no longer available, I'd suggest:
A) Google for companies that specialise in supplying spare parts for electrical tools. There are several I believe (though I don't know any off hand, sorry), and such firms often hold all sorts of weird and wonderful old spares parts;
B) From your drawing it looks a dead easy machining job for anyone with a lathe. Got one yourself? Know anyone with one? Any "jobbing engineering shops" near you? Any model engineering (especially steam) clubs near you?
C) Long-shot: Look for someone selling the same tool as yours SH.
Whereabouts in Germany are you?