Ian, did Backdraft say anything about you breaking your hubs??
Is it aluminum / special Backdraft machined piece? I'm kin of surprised a BMW piece would break like that.
The only scenario I could picture from your carnage, was your wheel going air-borne when you hit that bump, high rpm, then when it touched-down, it snapped the hub. How hard did you feel that bump?
We were behind you and saw you hit it, but didn't see you go flying into the air. I was more concerned about you trashing your oil pan.
Glad it's on the mend.