I have not been in the Forest Dean since I was a child. I cannot imagine wild boar running about. But should the collapse of civilisation not be far
off, many may be grateful for a boar to eat, or the skin of a lynx or wolf with which to keep warm.
An 'infestation' as you say of wild boar or feral pig is a terribly threatening thing. When food is scarce a boar will gladly attack and eat any
human being it can. They are amazingly destructive beasties.
We heard a big cat while we were there. And we only stayed one night. Not that catching a native British black leopard would be an easy task but I
like your view on this.
Without a well trained dog or a noisy rifle taking a pig could be tricky but possible with patience and knowledge.