There is significant damage from the failure.

The ball joint connecting the top control arm to the hub assy failed.

It appears to have gone with no warning, they are adamant that there was nothing wrong when they checked it. They noted some bits and bobs about the lower bushes getting tired but nothing else.

The bill includes

Replace control arm, failed
Replace brake discs, badly scored need to replace both sides, will resurface pads as they have plenty left.
Replace brake splash guard, destroyed.
Replace wheel arch liner, destroyed, they will also paint the body where the damage is to stop it corroding.
Replace drive shaft, this had failed (leaking grease) before the incident but I was ignoring it as alone is £700 to replace.
Replace air springs (pair), these are working but are very tired so may as well replace while its all in pieces to save some labour cost.
Replace wheel bearing
Replace tyre, ruined.

They have also found a fuel leak.

Its amazing how much damage was done, the control arm dropped onto the brake splash guard rolling it over the disc and grinding a hole into it before badly scoring the disc, the tyre rubbed the arch liner burning through it and into the bodywork underneath, trashing the inner wall of the tyre.

Its a fair chunk of work and parts so im not really surprised at the cost now I have seen it. They have dropped the labour involved in diagnosing it (over £100) and given me a loan car for the duration, so theres some good will from the dealer. I also get discounted labour and parts due to the age of the vehicle, I shudder to think how much it would cost without that!

The ball joint connecting the top control arm to the hub assy failed.

It appears to have gone with no warning, they are adamant that there was nothing wrong when they checked it.

Bollocks,
I'd be going to see a solicitor if it was me.

Any one remember moggy 1,000's and marinas at the side of the road with the front wheel hanging off, that's because mechanics! didn't know how to check them.

Yes, if you know how you can tell if a balljoint is on it's way out, the swedish MOT told me I had one I should replace before next years test so they knew it was faulty but not yet dangerous (otherwise it would not have passed).

http://www.realoem.com/bmw/showparts.do?model=NJ72&mospid=47762&btnr=33_1219&hg=33&fg=30

Item 20 theres a ball joint that connects the control arm to the hub

ahhh, that's a different diagram to the one I was looking at... odd use of a ball joint tbh

I'd still want to see it, and see how it failed

it's easy to be a keyboard warrior on here and say you should demand it all repaired for free etc... but the garage will tell you to shove it unless you have a decent reason/evidence behind it.... without that they'll just tell you to shove it

and tbh.... better of going to an independent garage

even the euro car parts type places can get genuine BMW parts for a fraction of the cost now (I know a bmw wings are £14 because a mate got one a while back)

if you give me your reg/model info etc.. and a list of parts, I could get them priced up for you.... main dealers normally have a 60% markup on parts to start with

if you could get parts at cost, and cheap labour you'd be onto a winner