I've done a bit of reading around and it seems there are 4 active categories of write-off:
A - can't be repaired and entire vehicle must be crushed
B - can't be repaired and body must be crushed, but other serviceable parts are salvageable
S - structural damage that can be repaired, and vehicle can be used once made roadworthy
N - non-structural damage that can be repaired, and vehicle can be used once made roadworthy
This Autocar article -
https://www.autocar.co.uk/car-news/advic...-need-know - gives the examples of "a bent chassis or creased door frame" as examples of repairable structural damage.
Apparently insurers consider a repairable vehicle a write-off (i.e. categories S and N) if the cost of the repairs amounts to more than half the vehicle's value.
As the damage on your B9 covers a lot of bodywork, it seems likely it would fall under category S.
This article by GoCompare is quite informative about what happens when a vehicle is written off -
https://www.gocompare.com/car-insurance/...y-c-and-d/ Surprise surprise, it seems like the insurance companies call the shots (it looks like if the vehicle is written off, but you want to keep it, then, having accepted an agreed settlement from the insurance company, you'll have to buy your vehicle back from them, at the price of 10-30% of its value....)