Typically for insurance purposes, repairers will take "the path of least resistance" to return a vehicle to pre-accident condition, so combining that fact with Robin`s statement, although £36k seems like a huge repair bill*, it could well have been more to repair rather than replace the body, on paper!!!
The cost of repair vs. value of vehicle wasn`t sufficient to class it as an insurance write-off, so no Cat C/D etc.
*I wonder if there were additional works carried out above and beyond the insured incident damage, at the same time, the difference between insurance payout & total figure having been paid for by the owner? We`re getting into the realms of the unanswerable here, I understand! [:I]