It’s welded to the heel board, and I’d like to replicate it, as some one has tried to remove mine with what looks like a knife and fork

Also, has anyone had any experience in fitting a load bay floor in a van? I’m doing the whole lot including bracing underneath. I’d like to leave the wheel arches in as they’re in excellent condition. Has anyone got any good pointers/ tips before the floor arrives?
Cheers, Oli