Electric accelerator is controlled though the engine ecu. So if you don’t want to have the electric type you need an ecu with this not on it. Also the cam and crank sensor. And wires for the wiring loom for the idle control and throttle sensor. As electric type don’t use them. If you want electric type you need the wiring looms and ecu and cam and crank sensors. So converting to electric you need the wiring looms and loom to the cab and a peddle pairs to the ecu and the throttle.
You will have to make a pedal up from Corsa B and Corsa C parts or try to import the cable pedal from SA or other countries that still used cable throttle on the Corsa C shell.
I doubt any of the few who went ITB on the Corsa C are still on here now? There maybe some pictures if you search "track car" or "itb's"?