hello mate
the sounder is under the scuttle on the left looking into the engine bay from the front of the car.
you have to take the wipers off 13mm nut under the covers then hide the swear box and get some new plasters and remove the scuttle. the sounder is the thing that looks like a car horn. the plug on it is a small thing with a clip on it. take the plug off and it will stop it sounding.
Just done mine, took me about 45 mins if you take off the times i kept coming in to check on lewis hamiltons amazing first win

Good luck
Tony