I don't understand why ATR would manufacture a repair.
Exactly what motivation is there for them?
It would be no skin off their nose to say it is unfit for repair and sell them a replacement airframe.
Any repair, even manufacturer designed, carries elevated risk of compromised structural integrity - and associated liability, especially as time goes on.
Tell them it's scrap and fly home to France. I would.
Why wouldn't ATR design a repair and get the aircraft back in the air? Not good for repetitive business if you don't provide support post sale....
Boeing send an army of engineers to fix aircraft that would be on the verge of being written off eg, VH-NXE in Darwin... Design the repair, new maintenance schedule covering the repair (if required) and away you go.