Yeah as above I wouldn't repair that at all. On occasion I have used CT1 to fix a SMALL hole. And save a bit of money on race day. Buy ideally any holes in bodywork is a safety and scrutinising/rule issue. Just get new tbf!
Know that one from junior - have given up to repair these bigger damages, but you could use construction foam to stabilize the internal and then some plastic padding for the finish - then you can continue to use it for practice runs.