[oldskool]

thats a tricky one Nick tbh - sorry to hear this

usually an insurer will try direct you to one of their approved bodyshops

if you are claiming off a third party you can choose to go to any body shop of your choice but if the repair they do is then not up to your standards i believe its largely between you and the body shop as you have chosen them albeit by submitting quotes from them

imo contact the bodyshop as well as the insurers to see if payment can be halted until you are satisfied and the car is at minimum safe

i had similar with a landy a few years ago but luckily the bodyshop agreed the work was substandard and redid the whole job as well as supplied a loan car from their pocket