I cleaned up the replacement carpet tonight
Halfway through
All done. This can dry overnight and will go back in tomorrow.
I replaced the driver's seat belt reel with a good one and plugged it back in properly, and then replaced the airbag controller which solved the 'crash signal implausible' stored in the ECU. Implausible - crashed and not crashed at the same time?
More likely it just got damp.
The replacement airbag controller is showing almost all the codes it knows about with the interior being missing, but its not showing a code for the driver's seat belt tensioner so thats good.