Glad to hear that you're OK chopobo.
I saw a nasty accident last night, and when I saw the title of this thread I got a bad feeling in the pit of my stomach.
It seems that everyone is forgetting that when you buy a car privately, that the onus is on you to check that there is nothing wrong with it.
Once you have the car in your possesion, its upkeep is your responsibility.
Once upon a time, I purchased a car that blew a head gasket 3 days after I got it, but I had no comeback, I paid for the car, and I couldn't do a damn thing about it.
Even if you buy from a car yard, they will only fix mechanical problems, (and I'm sure they'd find a way to get out of a problem like this one)
You are lucky that they are taking care of you so well.
And as for the locknuts, theyre just a special type of nut that you need a certain type of socket for (meaning that the regular joe blow on the street can't take them off with his standard tyre iron)
Good luck with it all, and hope to see you safely on the road soon!