It must be a different gearbox, as the diesel engine, even in race trim, will chuck out twice as much torque as a petrol one, and its usually torque that kills gearboxes (this is from someone putting 180 ft lb through a box originally designed for 60)
The answer may be with the new Bugatti, which has a British 4WD gearbox for the 1,000 bhp motor. Coincidence