Mine has a huge hole all the way down from under my ecu to around the screenwash filler neck!
I can weld but i just cba to do it just yet, got a solid piece i have cut out of my breaking saxo ready to weld in properly and paint but its just finding the time and space to do it these days
and if you just plate that hole mate it will still rust from the other side! i would cut it out and weld a new bit in and then protect and paint