you let him drive the car from the workshop unregistered?
i'm sure it would be your duty of care to NOT let him take the car... and i'm sure that if he did have an accident he could probably successfully sue you for it
i dont know you, or josh
it seems he was stuffed around on paperwork and his address going missing on the few occassions would not cut it for me at all.. Im sure anyone would get annoyed over being stuffed around..
Now... there is no point coming on here and starting a fight, all workshops have their up's and downs here and there... this happens to be a down, the dyno day 2 weeks ago was an up.. just leave things as they are and move on