I can see him losing that argument if he has refused to use 'his' car pending the repair
Sounds like he's dug his heels in and they've gone out of their way with the CLS when they could just as easily given him a base A Class to run around...
It came to a head when that hot weather we had earlier in the summer was predicted, as his dealer up til that point fobbed him off previously (the fault has been ongoing since at least March), and then when he pressed the point that it was gong to be 37C, was given him stupid dates to even book it in to look at it - which leads me to suspect there is a known issue, so they try to delay each stage - so he did drop it off and told them he was leaving it there until they fixed it, as he could foresee it not being fixed before it gets handed back in a little over a year.
I believe the CLS has come from MB UK, not the dealer, but could be wrong. I did spend a lot of the time laughing as he was recounting the saga. As you would, really.