I'd think that the reason why you are not finding places like ECP listing these stub axles is that they will only stock products that move fast and frequently.
Two places to get a stub axle, scrappy or any VW Group dealership, they would need to order one in from the main warehouse as again that will not be a frequently asked for part.
Like Crossthreaded I think that any surface damage on that stub axle could be tidied up wit a bit of time and care using basic hand tools, plus greasing the stub axle to
help things along.
I'd also guess that in 95% of cases, the only reason to replace a stub axle is because the car had been kerbed heavily and so after carrying out alignment checks, that stub axle was proved to be bent - which is not the sort of issue you are having.
Also I think that there is a spacer pressed onto that stub axle, so buying a new stub axle would just give you a new plain stub axle, you world also need to order in a spacer and get a workshop to press the spacer on to it - though I could be wrong there, I'll check up a parts listing and edit this posting.
So, in your shoes, I would spend a bit of time finding out where the damage was on that stub axle and tidy it up using an old bearing inner race to prove all was well then fit the new hub assembly when you get it. Only then after failing to get things sorted out would I try to get a stub axle from a scrappy - if in deed they are willing to separate it from the axle and not try to sell you the complete rear axle assembly.
Getting back to "ends of the road wheel bolts fowling the brake shoes yoke - something not right there, are the wheel bolts the original VW Group supplied ones, ie 46-47mm in length overall or 26-27mm in length from the base of the spherical seat, and genuine VW Group wheels?
Edit:- I am wrong, there is no separate spacer on the rear axle stubs, it is one piece.