Can we confirm that the wheel was not changed at service/repair time and an apology has been given to said garage or are we just covering this up with the milage thing?
Having spoken with someone who used to work in a dealership, at a high level, I've been advised whilst possible I will have a job on my hands to prove it.
I am not covering up anything, I will mention the wheel and have them check date stamps to confirm/dispel my theory. I am adamant I had two matching tyres post puncture on that axle, and have been trawling through my pics of the car to try and see if I can prove this one way or another.
Its been in MB Glasgow before the pic where people say that shows an Eagle F1, and was given back with a wheel (either mine or someone elses) minus a wheel centre, whether this was a swap or just my wheel minus a centre I do not know by my gut/memory goes with 2x same tyres on that axle as I paid for: Furthermore I have a receipt for a new good year efficient grip tyre which was fitted to passanger front side of the car. Sadly the bill just says which tyre, and not the side it was fitted to, so MB Glasgow could easily say, that could be fitted to drivers side, and its a case of my word vs. them.
Proving this is nigh on impossible and as its me saying "you've done this" the onus is really on me to prove it, and I cannot. Sadly the days have gone when someones word was enough, and this is the world we live in and I will have to deal with this.
I need to query the mismatching report and mileage thing, but I have paid for a ball joint, and that IS what is there, so I am wrong in saying they have ripped me off, what is there is what was paid for. I do not want to take something needlessly for nothing, I will not be a freeloader.
I will not take my car their again, until I hear of reports of better service (a few in the know have said its gone downhill) so I will not take anything from them to make me go back, as its not my intention now to do so, otherwise to sort out the issues I have. I am not a liar, and will not deceive them into giving me something, unless proven they are wrong, on the basis from more business from me. The failure to fix my gbox fault, confusing me with someone else and them calling the wrong customer IMHO is enough cause for me not to go back.
Back to the ball joint: the onus on whether MY car needed this part is again on me, and minus the old part I am probably not with a good case, although the mileage and treads reported on that report to not tally really to my car, but I can discuss this with them tomorrow. Whether there is a typo on that report, and whether I can prove they looked at the wrong car, again lies with me.
PS, all around the new ball joint is all scuffed and scrapped. The otherside where there is another newish ball joint is ok. They've made a mess of my car there. I'll raise that. And yes, the scuffs are fresh can be proven.
I fully sympathise with what you are saying and hope you get the matter resolved but in the bigger picture I'm not sure if the regulatory authorities or MB UK would feel its a priority? 
