So clearly the A330 does experience high speed buffet.
The A330 only experiences high speed buffet below Mmo at substantial 'g'. Pulling more 'g' increases the buffet, and less 'g' reduces buffet or gets the airplane out of it. So for recovery from buffet is doesn't really matter whether it's low or high speed buffet: stop pulling, pitch down, not up, gets the airplane out of buffet. Correcting the airspeed comes next - same as for stall recovery.
Buffet is a function of angle of attack and Mach number. Angle of attack is managed with the pitch control, airspeed is managed with thrust and drag and flight path angle.